The arrest of a 32-year-old Algerian man attempting to enter the United States with nitroglycerin and other bomb-making materials has led federal law enforcement officials to believe that a major terrorist attack was being planned to take place on U.S. soil during the holiday season.

Washington state police said yesterday that the man, Ahmed Ressam, was transporting two 22-ounce bottles of nitroglycerin, more than 100 pounds of urea and homemade timers in his rental car when he was caught earlier this week in Port Angeles, Wash., as he arrived by ferry from Canada. Urea, which can be used in fertilizers and explosives, is the same substance employed in the 1995 bombing of the Oklahoma City federal building.

One law enforcement official said U.S. intelligence agencies were pursuing possible links between Ressam and Osama bin Laden, the millionaire Saudi militant based in Afghanistan. Terrorism experts said the detonating device that Ressam carried--circuit boards linked to a Casio watch and a nine-volt battery--was similar to one used earlier by associates of bin Laden.

"The way this bomb was put together, particularly the use of the Casio watch, is a signature of the bin Laden organization," said Vincent Cannistraro, former head of counterterrorist operations at the CIA.

The FBI and the CIA have taken over the investigation from the U.S. Customs Service, whose agents arrested Ressam when he attempted to flee after being questioned and asked to step out of his rental car. Authorities said yesterday he was bearing a false Canadian passport and driver's license with two different names.

"We have found enough evidence to make us believe this was not a run-of-the-mill operation by this guy," said a Clinton administration official. "This was serious."

The official added, however, that a definite link to bin Laden's organization had not been established, and he noted that a State Department warning last weekend about possible attacks on Americans around the world was based on concerns about more than one terrorist group.

At an initial court appearance yesterday in Seattle, Ressam was charged with knowingly transporting explosives across the Canadian border, having false identification papers and making false statements to U.S. Customs Service officials.

Law enforcement officials said they strongly believe Ressam had accomplices, and one source said the FBI believes he might have been carrying the bomb-making materials for someone else to plant.

U.S. officials released little information about Ressam, who is scheduled to be arraigned Wednesday. They said he speaks French and Arabic, and had planned to stay at the Best Western Loyal in downtown Seattle, close to a variety of holiday events, including a New Year's Eve celebration five blocks from the hotel at the Space Needle.

He also had a reservation Wednesday on an American Airlines flight from Seattle to New York with a stop in Chicago, and a ticket for a connecting British Airways flight to London, the Associated Press reported.

According to the Seattle hotel's desk clerk, Brian Ross, a reservation was made Dec. 14 through the Best Western national 800 number for a "Benni Norris," the false name U.S. Customs officials said was on Ressam's fake passport. The person who made the reservation left a credit card number and a contact telephone number in Quebec, Ross said. The FBI has confiscated the hotel reservation records.

Concern about possible attacks coordinated by bin Laden was heightened this week by the arrest of 14 of his alleged associates in Jordan and Pakistan. They allegedly were plotting attacks on tourist sites and American travelers during millennium celebrations.

A man identified yesterday by Jordanian authorities as Khalil Deek was extradited from Pakistan on Thursday, two days after he was apprehended in his home in Peshawar on that country's border with Afghanistan, the Associated Press reported. Deek is believed to be the head of the terrorist cell that includes the other 13 people arrested in Jordan, a Jordanian official told the AP. Deek is of Palestinian extraction, carries a U.S. passport and is sought by U.S. authorities for links with bin Laden, according to the Jordanian official.

Two more suspects remain at large outside Jordan, the official said.

Bin Laden has been indicted in the United States on charges of conspiracy and murder in the 1998 bombings of U.S. embassies in Kenya and Tanzania that killed 259 people. He is living in Afghanistan under the protection of the ruling Taliban militia.

Cannistraro, the former CIA counterterrorism expert, said bin Laden is believed to be receiving new assistance from the Taliban. Almost 500 of bin Laden's men have died fighting for the Taliban against rivals in the northern part of the country, and the Taliban is now reciprocating by providing his agents with fake passports and travel documents, he said.

Cannistraro added that the increased logistical help from the Taliban might be an unintended result of the tightening of sanctions against the Afghan regime by the United States and the U.N. Security Council, which has given the Taliban less to lose.

Although Ressam was carrying a smaller quantity of urea than was used in the Oklahoma City blast, Bruce Hoffman, a Brookings Institution expert on terrorism, said it would still have been enough for "a nice-sized explosion."