WASHINGTON -- Absent hard evidence about motivation, the Bush administration is considering the possibility that foreign or domestic terrorists are behind the sniper slayings of nine people in and around the nation's capital.

Homeland Security Director Tom Ridge said Tuesday that investigators are hesitant to rule out any possibility.

"Under these horrific circumstances, you don't want to draw any premature conclusions," he said. Regardless of whether the attacks are the work of terrorists, he said, "The community is terrorized."

All 11 sniper victims -- nine killed and two wounded -- were gunned down while performing everyday tasks such as filling their gas tank, loading groceries in a vehicle and going to school.

Senior Bush administration officials monitoring the case said that until evidence surfaces to the contrary, domestic or international terrorism cannot be ruled out.

However, the consensus among the officials is that the sniper is American because the crimes do not bear the traditional hallmarks of an international terrorist attack -- nobody has claimed responsibility and U.S. intelligence has not heard chatter about the attacks.

President Bush on Monday called the sniper a cold-blooded killer and the attacks "a form of terrorism."

But terrorism experts say the shootings should not be classified as terrorist acts because the sniper has not given a reason for the shootings.

"It's important to remember that everything that terrifies is not terrorism. Terrorism is a specific kind of political violence," said Donald Hamilton, deputy director of the Oklahoma City-based Memorial Institute for the Prevention of Terrorism. "It doesn't make the victims any less dead, it doesn't make it any less terrifying, but it's worth noting."

In the 1995 Oklahoma City bombing, Timothy McVeigh didn't reveal any political motivation until after he was arrested.

In this case, too, Ridge indicated the motivation may well not be known until the sniper is caught.