-- Greek officials are conferring with antiterrorism experts from seven nations and investing unprecedented sums of money in security operations as they prepare for the 2004 Summer Games, which will be the most heavily protected and perhaps most uneasily watched in Olympic history.

Motivated by the volatility of a post-Sept. 11, 2001, world, the memory of two Olympic Games marred by deadly violence and Greece's proximity to unstable regions, Greek and Olympic officials are soliciting advice from a ring of international advisers and have made security their most pressing concern even though the Games are about 19 months away. The Greek government has earmarked a minimum of $600 million for security infrastructure and equipment -- the total may approach $1 billion -- and designated 45,000 full-time uniformed personnel for the Games.

The security budget will more than double that of any previous Olympics. The number of personnel will obliterate previous totals by a factor of four. And the extent and formality of the international networking, though in step with the collaboration that has characterized the global fight against terrorism in the last year, represents a new approach to Olympic security.

The Olympics are "everyone's issue," said David Tubbs, a former FBI agent who oversaw security operations at the Salt Lake Olympics in February and is now the vice president for security events for Science Applications International Corporation, which is bidding for a security contract for the 2004 Games. "It's really a mutual protection society."

Athens 2004 security consultant Peter Ryan, also the lead security officer in Sydney for the 2000 Summer Olympics, said the teamwork and expenditures are not merely resourceful, they are necessary to meet the basic security demands of the Olympics -- which will bring 10,000 athletes in 28 sports to Athens for 17 days -- at a particularly perilous time in world history in a region with a unique and daunting set of challenges.

"The cooperation is vital," Ryan said. "The intelligence community is really rediscovering itself in terms of international cooperation."

The Salt Lake City Games took place without incident just months after Sept. 11, but the Winter Olympics are about a third of the size of the Summer Games, and Salt Lake City's relative isolation allowed for the essential equivalent of a security fence to be erected around it by a unified team of U.S. forces governed by the Secret Service.

Such will not be the case in Greece, a nation of 11 million that straddles the Balkans, is a neighbor to the Middle East and North Africa and is so open to visitors that its population doubles annually as tourists stream in to see the nation's ancient monuments or cruise to its myriad islands. Unlike in Salt Lake City, shutting down airspace will require the cooperation not merely of neighboring locales, but of neighboring nations -- including Turkey, with which Greece has long had strained relations. And Greece will have to protect venues not just on land, but at sea, as various VIPs and corporate sponsors will stay in floating hotels -- cruise ships -- in Athens's main harbor.

"With the borders the way they are now in Europe, along with the harbor issue and the air-cap issue, they're facing some very strong problems," Tubbs said. "If someone wants to make a statement, instead of being 14 hours away, they're 11/2 hours away."

The money designated for security by the Greek government and Olympic organizers dwarfs the $310 million invested during the Salt Lake Games, the $210 million for the 2000 Games in Sydney and the $300 million spent on the 1996 Summer Games in Atlanta. Greek Minister of Public Order Michalis Chrysochoidis said the full allotment of security funding came in response both to stiff IOC requirements -- Athens needed to start from scratch in a number of areas -- and the recognition after Sept. 11, 2001, that cost-cutting could not be tolerated.

It was Chrysochoidis who decided to create the Olympic Security Advisory Group, the team of seven nations with experience in handling terrorism and holding big events that has been meeting quarterly in Athens for the past couple of years. The United States, Britain, Spain, France, Germany, Israel and Australia compose the group. Thomas J. Miller, the U.S. ambassador to Greece, said the meetings have allowed numerous counter terrorism experts from the participant countries to discuss everything from securing the congested roadways in Athens to identifying potential targets for terrorism. Greece also has signed 37 security agreements with 22 nations.

"I saw that we needed the international cooperation, because these countries have experience," Chrysochoidis said. "It was a very positive initiative."

U.S. Olympic officials have made specific requests to Greek officials about safety concerns of U.S. athletes and officials and received assurances that the U.S. contingent will receive the highest levels of protection available. Miller added that the U.S. personnel involvement with respect to security would see a ramping up in the coming months to previously unmatched levels for an overseas Olympics.

"I can't begin to tell you how big a priority [the Olympics] is for us now, in the effort and energy we're putting into it," Miller said. "It's not too early."

Though Olympic security has been a major priority since 11 Israeli athletes were slain by terrorists at the 1972 Summer Games in Munich, never before have security preparations been threaded by such a consistent and formalized international network. In November, training exercises that involved the simulated hijacking of a plane and ship were conducted in Athens with assistance from antiterrorism experts from London's Scotland Yard.

It was just 61/2 years ago, at the 1996 Olympics in Atlanta, that security was essentially a one-nation operation, and poorly handled at that. The security at those Games was paid for largely through private U.S. funds and divvied up among a hodge-podge of local, state and federal agencies in a disjointed arrangement later criticized by both the IOC and the officials involved. Those Games were tarnished when a bomb exploded in the central Olympic park, killing one person.

"It takes just one thing to happen and the reputation of the Games is forever marred," said Ray Mey, the FBI representative in the Department of Homeland Security who has helped coordinate security at the last four Olympics. "Can you stop everything? In reality, no, but you can really put a lot of things in place to enhance the possibility of being totally successful and that's what costs. It's not wasted money. It's not excessive."

In a development considered crucial to the credibility of Greece's security efforts, the Greek police -- helped by teams of U.S. and British agents -- have in recent months staged an encouraging crackdown on once-rampant and seemingly unchecked terrorism within the nation's borders. After more than 25 years of terrorist activity from the radical group November 17, which has been blamed for more than 20 political assassinations and four dozen bombings, 18 suspected members have been taken into custody within the last six months and are scheduled to go to trial in March. Among the murders attributed to November 17, which takes it name from the date of a 1973 uprising by students against Greece's then-military government, was the 1986 assassination of Dimitrios Angelopoulos, a relative of Athens 2004 President Gianna Angelopoulos-Daskalaki.

"It is very encouraging because it shows the ability of the Greek police, but it doesn't make us relax," Angelopoulos-Daskalaki said of the captures. "We know we have to remain vigilant."

The arrests brought enormous relief to the Greek government, which was publicly challenged by U.S. and other international officials to explain how it could defend against international terrorism during the Olympics when it couldn't combat terrorism within its borders. Chrysochoidis declared during a recent interview that the fight has been won.

"We are very sure we have finished with internal terrorism in Greece," he said. "We have arrested all of them . . . [and] we have finished with a very big problem."

That confidence may have been shaken by an assassination attempt last month on Athens's mayor-elect, though no connection to November 17 has been suggested. The shooting was attributed to a former psychiatric hospital patient.

U.S. officials, somewhat less optimistic than Chrysochoidis about the finality of the breakthrough against November 17, say Greece's primary strength in handling security will be its well-defined chain of command. Such clarity of operations was lacking in Atlanta, and it was pieced together in Salt Lake City only through a 1998 presidential order that placed Olympic security under the direction of the Secret Service in time for the 2002 Winter Games.

Greek law dictates that the Greek police, which are housed in the Ministry of Public Order, oversee Olympic security through a special unit, the Olympic Games Security Division. That division is ultimately responsible for all of the planning and coordination. Among those taking orders will be the Greek military, which, unlike in the United States, does not face restrictions regarding its use. Salt Lake City officials wrung their hands endlessly over various prohibitions governing the use of military forces, such as a restriction banning soldiers from patrolling U.S. streets in undeclared emergencies.

"They have resources we were not able to have," said Robert L. Flowers, the chair of the Utah Olympic Public Safety Command, which worked with the Secret Service to coordinate operations during the Salt Lake Games.

Other issues, however, haunt Greece's preparations. Barely a brick has been laid for a cluster of venues at the site of Athens's old airport in Helliniko. Other venues, including the Olympic Village, are not yet complete. Various extensions of roads and railways exist only as blueprints.

"Security can only come off the drawing board after the venues have been constructed," said Mark Camillo, a deputy special agent in charge in the Presidential Protective Division at the White House who was part of the Secret Service operation in Salt Lake City. "Prior to that, everything has to be done conceptually and on paper. . . . We can empathize with the Hellenic Police. We were in the same situation; we had to wait for [some] venues to be completed."

There also has been sluggishness in awarding a contract for a central command and control system to one of two competing U.S. companies, Raytheon and SAIC. Chrysochoidis said a decision is expected within the coming weeks. Security officials say it's imperative that work begin soon for the successful installation and testing of a system will provide the Greeks with everything from high-tech heat and motion sensors to digital recognition equipment.

Ryan insists that security preparations are on or ahead of schedule if measured against security timelines of Salt Lake City and Sydney. On a recent Friday night in Athens, air traffic controllers at Athens's new international airport received reports that a 737 aircraft bound for Athens had been hijacked by a group of terrorists. Almost simultaneously, radicals stormed a large passenger ferry docked at Piraeus port. Soon, reporters from CNN and local newspapers were on the story, demanding information. Relatives of the passengers sobbed and pleaded with Greek officials during on-air interviews.

It was all part of an extravagant training exercise -- a painstaking, expensive one that involved 1,800 officials and volunteers and required nearly two full days to resolve. With the input and assistance of Scotland Yard and various international officials, the Greeks stocked a real airplane with some 200 volunteer passengers and a handful of pretend terrorists. They also summoned about 150 willing observers onto the ferry, which was raided by another group of faux radicals. Volunteers played the hounding media, and others shed tears as distraught relatives. Toilets on the plane overflowed. Passengers fell ill from exhaustion and hunger -- all ploys to increase the pressure on the Greek authorities who were being tested.

Finally, Greek military members stormed the plane and cruise liner the ensuing Sunday morning, rescuing the passengers and overtaking the terrorists. As something of a denouement, the passengers had to be debriefed.

Food was ordered for them, and hotel rooms were secured. No detail, Ryan said, was considered too inconsequential to rehearse.

"Since September 11, we factored into all of our thinking literally the worst-case scenarios you can imagine happening anytime or anywhere," Ryan said. "The world is far, far more uncertain now than it's ever been, but a lot of effort is going into this."

Anti-terrorist squad conducts exercises on cruise ship in port city of Piraeus, just outside of Athens, in preparation for the Summer Olympics in 2004.Athens 2004 consultant Peter Ryan says security arrangements are on or ahead of schedule compared with Salt Lake City in '02, Sydney in '00.