RENO, Nev. (AP) _ A bomb was discovered this morning outside an Internal Revenue Service office, and the building was evacuated, police said.

The bomb, contained in a 25-gallon plastic drum on a dolly, was found in a parking lot. The device had a fuse attached that had been lighted but had gone out, said police Lt. Ken Bunker.

He estimated that an explosive device of that size could have damaged a number of cars and blown out windows facing the lot.

``When we make sure it's safe to move, we'll take it out somewhere to a safe area to either detonate it or dismantle it,'' said police Lt. Phil Galeoto.

Authorities evacuated the two-story IRS building and a dentist's office next door while the bomb squad examined the device. About 70 IRS employees work in the Reno office, including about 60 who were inside when the device was found at 7:42 a.m., Bunker said.

Four federal agents from the Bureau of Alcohol, Tobacco and Firearms went to the scene, said spokesman Richard Stoltz.

Three bombings in the Reno-Carson City area in recent years have been aimed at federal government targets.

The Bureau of Land Management building in Reno was bombed on Halloween 1993. Its roof was heavily damaged, but the building was empty at the time.

On March 30, a pipe bomb slightly damaged the U.S. Forest Service office in Carson City. It, too, was unoccupied. On Aug. 4, a pipe bomb damaged the parked vehicle of Forest Service District Director Guy Pence at his home in Carson City. He was away at the time, but his family narrowly escaped injury.

No arrests have been made in any of the incidents.