The FBI said Thursday it has identified elements of international terrorist organizations in this country, but FBI Director William S. Sessions said Americans should "go about our business" as usual.

Sessions stressed that the threat of international attacks in this country was low despite the outbreak of war in the Persian Gulf."The bureau feels it is very much in control of the counter-terrorism program," Sessions told the midwinter meeting of the U.S. Conference of Mayors. "I think we ought to go about our business."

But one of Sessions' top aides said the FBI had identified what he called the infrastructures of several international terrorist organizations in this country.

William Baker, head of the FBI's criminal investigations division, said supporters of international terrorist organizations were present in this country. He listed those organizations as the Abu Nidal organization, Hezbollah, the Palestine Liberation Front, and the Democratic Front for the Liberation of Palestine.

"All of these organizations have the capability of having contact from abroad and could carry out activity in our country," Baker said.

Despite this, Baker said, "We continue to see a rather low level of activity within the United States."

Baker said the highest potential threat was from the Abu Nidal organization, which threatened attacks on U.S. installations worldwide following the recent deportation of Mahmoud el Abed Mahmoud Ahmad Ata, one of its North American leaders. He was deported to Israel, where he was wanted in connection with a 1986 firebombing of a bus that killed the driver. The deportation occurred before the war against Iraq began.

Asked to define terrorist infrastructures, Sessions compared them to a business in which each person has a particular responsibility.