Terrorists and insurgents are stepping up attacks on oil and gas operations overseas in an effort to disrupt jittery energy markets, destabilize governments and scare off foreign workers, analysts said.

The attacks have been most intense in Iraq, but also have occurred in recent months in Indonesia, Pakistan, India, Russia and Nigeria.

In many cases, the attacks are orchestrated by terrorists or rebels, often Islamic extremists, seeking to cause economic disruption or steal oil to finance their operations, analysts said. Their targets are sometimes pipelines, tankers and workers in areas with varying levels of security.

"You have motive and opportunity, so you're seeing more of this," said Anne Korin, director of policy and strategic planning for the Rockville-based Institute for the Analysis of Global Security, which tracks attacks on oil targets. "It's a very effective strategy on their part. . . . Oil is really a very target-rich area."

Korin said that terrorists find it easier to go after energy, which she called "our soft underbelly," because the targets often are convenient and have a high impact. They can be found near terrorists' home bases and in areas where there may be less security than in the United States.

Al Qaeda has repeatedly noted the appeal of oil targets, intelligence analysts said. Documents from the terrorist organization, obtained and translated earlierthis year by IntelCenter, an Alexandria company that provides risk assessment and terrorism information to government and businesses, calls for "hitting wells and pipelines that will scare foreign companies from working there and stealing Muslim treasures."

That document also highlighted as a "practical example" a 2002 suicide bombing attack on a French-chartered oil tanker off the Yemeni coast, killing a crew member and spilling 90,000 barrels of oil into the Gulf of Aden. Last month, several militants were convicted in Yemen for their roles in the tanker attack.

The attacks come as the world's oil production is stretched close to its limit. Analysts view the persistence of the attacks as a factor that adds pressure on oil prices. High prices have been cited by the Federal Reserve as contributing to slowed U.S. economic growth. On Friday, U.S. benchmark crude for November delivery closed at a record $48.88 on the New York Mercantile Exchange.

No complete statistics exist on the number of oil and gas targets hit worldwide. In Iraq, the attacks have steadily increased this year from two in January to 18 in September, as of Friday, according to the Institute for the Analysis of Global Security. In a high-profile incident Thursday, gunmen killed a top Iraqi oil official in Mosul and attacked a pipeline in the south and a well near Baghdad.

The Iraq attacks have been causing huge disruptions in the country's oil production and resulting in millions in losses to the government.

Outside of Iraq, armed men stormed a gas tanker at anchor in Indonesia in July. The same month, attackers blew up oil and gas pipeline in various locations in India. Oil and gas pipelines also were blown up in Russia in June and August.

In Nigeria in April two Americans were shot dead aboard a boat that was returning from a ChevronTexaco oil platform in Nigeria.

"Oil is just very much in the crosshairs around the world," said John Kilduff, senior vice president for energy risk management at Fimat USA in New York, a brokerage unit of Societe Generale. "There's no country, there's no production that can come to the rescue of any kind of terrorist attack."

Kilduff said oil markets are most concerned about attacks on Saudi Arabia, the world's largest oil exporter. Those fears have been heightened since May when a group associated with al Qaeda claimed responsibility for an attack on foreign oil workers that left 22 dead in the Persian Gulf city of Khobar. In the first day of trading on the New York Mercantile Exchange after the attack, U.S. benchmark crude futures jumped $2.45, or 6 percent.

The Iraq attacks have multiple purposes, analysts said. Some are designed to curtail exports and cost the country money, adding to expense of the U.S. of reconstructing the country. Other attacks are designed to cut natural gas flowing to power plants as a way to cause power outages and spark dissatisfaction among Iraqis with the country's U.S.-backed government, analysts said.

Pipelines such as those in Iraq and other Middle Eastern countries stretch for hundreds of miles, are often unguarded and make easy targets, analysts said.

"They are just sitting there with a bull's-eye on them saying, 'blow me up,' " said Neal Adams, a Texas-based consultant who advises companies about terrorism and oil targets. "The easiest way to have an impact is with the pipelines . . . The pipelines in the Middle East are the big weakness. The terrorists can attack them all day long."

The pipelines often are above and below ground, and their locations are typically marked with signs warning against digging. The pipelines often can be repaired in a matter of days, depending on their location, but frequent attacks can cause severe disruptions, Adams said.

The attacks on energy targets overseas have been increasing since Sept.11, 2001, analysts said. Terrorists have found that such attacks have the largest impact because of the importance of energy to world economies, they said.

Bruce Hoffman, a terrorism analyst who heads the Washington office of the Rand Corp. said al Qaeda favors economic targets because they have a "force multiplying effect" by creating the impact of the attack as well as economic repercussions.

Attacks on oil targets can further terrorists' aims by destabilizing the country where the attack occurs as well as causing economic problems in the United States or other western nations, analysts said.

After the French ship attack, al Qaeda leader Osama bin Laden released a statement that, according to the IntelCenter, said: "the mujaheddin hit the secret line, the provision line and the feeding to the artery of the life of the crusader's nation."

In some instances overseas, where terrorists have been thwarted by high security from attacking oil equipment, they have found that killing foreign oil workers has a similar effect by causing them to flee and reducing production, analysts said.

To reduce the impact of attacks against oil targets, Korin said that the United States needs to wean itself from dependency on oil. She said her group and others will outline what steps should be taken today, following a conference on the threat posed by terrorism to energy operations.

A worker fixes a pump last week at an oil well near Baghdad. Attackers also target pipelines and tankers in areas with varying levels of security.