2:42 AM PDT, August 20, 2003

BAGHDAD, Iraq -- FBI agents led the search for clues in the rubble of a bombed U.N. compound in Baghdad on Wednesday, while U.N. Secretary-General Kofi Annan said the deadly attack would not drive the world body out of Iraq.

United Nations workers were told to stay at home Wednesday after a cement truck packed with explosives blew up outside the offices of the top U.N. envoy in Iraq, killing him and 19 other people. At least 100 people were injured in the unprecedented attack against the world body.

Annan said he was to meet with the Security Council later in the day to discuss security arrangements for U.N. workers in Iraq.

"We will persevere. We will continue. It is essential work," Annan said at a news conference in Stockholm, where he stopped briefly before heading to U.N. headquarters in New York. "We will not be intimidated."

Annan said the U.N. plans to reevaluate its security measures.