The U.S. government renewed its call on Monday for Americans to leave Saudi Arabia (search) after the recent terrorist attacks, saying the safety of U.S. workers was more important than any effect on oil supplies or the Saudi economy.

An estimated 35,000 Americans have been working in Saudi Arabia and it was unclear how many have left since the increase in attacks, which have come at the same time the Bush administration has been pressing the Saudis to boost oil production to help lower gas prices in the United States.

Referring to U.S. workers in Saudi Arabia, State Department (search) spokesman Richard Boucher said, "We first and foremost have a responsibility to Americans. We need to give them our best advice on how to handle any particular situation overseas."

"As far as the maintenance and continued flow of oil and the economy in Saudi Arabia, that is something I think the Saudis will have to describe, what provisions they can make and how they can operate those facilities."

He would not say how many American workers had chosen to remain in Saudi Arabia as part of the kingdom's huge expatriate work force.

"In this kind of situation, we feel that giving out numbers just identifies how many potential targets there might be," Boucher said.

The U.S. government is in close touch with Saudi authorities investigating the apparent kidnapping of the latest American victim, Paul M. Johnson (search) of New Jersey, who worked on radar systems of Apache helicopters for Advanced Electronics Co., Boucher said. The Saudi firm has U.S. defense giant Lockheed Martin among its customers.

By targeting foreigners' housing compounds, the attackers focus on a sizable sector of the Saudi economy. Saudi Arabia's own population is 17 million, and there are an estimated 8.8 million expatriate workers.

Westerners work in oil, banking and other high-level businesses. Some have moved up plans to leave on vacation and will decide whether to return depending on whether violence persists. Others are leaving for good.

Johnson apparently was abducted Sunday by militants who also claimed responsibility for gunning down another American from the same firm the day before. They threatened to treat the captive as U.S. troops treated Iraqi detainees, a reference to the month-old abuse controversy at Abu Ghraib prison.

Boucher said a U.S. Embassy message in Saudi Arabia "encourages Americans living there to practice good personal security procedures ... to report anything unusual to the Saudi police, and reminds them that the current travel warning ... urges U.S. citizens to depart and for visitors to defer travel."

Islamic fundamentalists apparently linked to Al Qaeda have been targeting Americans and other Western interests as part of a campaign to overthrow the Saudi monarchy in power since the 1930s. They consider the Saudi establishment too hospitable to Americans and other foreign "infidels."

The U.S. government has been urging Americans to leave Saudi Arabia for two months, and White House spokesman Scott McClellan said Monday that Americans should "take those advisories very seriously."