The threat came during morning working hours, some 12 hours after terrorists attacked the World Trade Center in New York and the Pentagon in Washington.

Police confirmed that a threat had been phoned in from a public telephone to Petronas' building management about 8:30 a.m. and that the caller said that a bomb would explode at 9 a.m.

Police said that people would be allowed to return to work once the building was declared safe.

Police officials said that no chances were being taken in the wake of the attacks in New York and Washington, where a hijacked jetliner was also crashed into the Pentagon.

Workers and witnesses said that thousands of people in both the 1,483-foot towers were told to leave the buildings. When they reached the ground, they were told there had been a bomb threat.

''We were told on the P.A. system that there was an emergency situation at the towers, so we were asked to evacuate,'' said Tarajit Singh, a finance supervisor for Petronas, the national oil company.

''We had to walk down and leave the building,'' Tarajit said. ''I walked down 58 floors. Only those who were sickly or expecting got to use the elevators.''

About 2,000 people milled around the wide esplanade and park around the building. Police and fire crews were on standby.