SAN SALVADOR, El Salvador -- Leftist guerrillas fired submachine guns and a rocket-propelled grenade at the U.S. embassy, blowing a 20-foot hole in the mission that has been attacked by terrorists four times in three weeks.
No one inside the embassy was injured in Wednesday's attack, but witnesses said two men in a passing bus were wounded by embassy guards -- including U.S. Marines -- who fired at the fleeing guerrillas.
An embassy spokesman, however, insisted there were no injuries.
Guerrillas from the leftist Popular Liberation Forces claimed responsibility for the attack in telephone calls to news organizations. They said it was in retaliation for U.S. military aid to the ruling military-Christian Democrat junta.
The guerrilla group said it had dedicated the embassy attack to slain San Salvador Archbishop Oscar Romero, who was gunned down by a presumed rightist a year ago.
The grenade attack was the first major guerrilla operation since the end of a 24-hour cease-fire Wednesday honoring the first anniversary of Romero's death. Judicial authorities reported 27 more deaths in political violence across the tiny Central American nation.
Twelve guerrillas, assembled at a parking lot across the street from the fortress-like mission, opened fire with submachine guns at 4:10 p.m. while one attacker fired a hand-held grenade launcher, embassy spokesman Howard Lane said.
Embassy sources said the rocket-propelled grenade hit the mission's third and tore out a 20-foot window of an unused conference room next door to the office of American charge d'affaires Frederick Chapin.
The blast ripped out most of the window's concrete framing, leaving a gaping hole in the blackened, bullet-scarred wall, Lane said.
In an apparent diversion, the rebels tossed a hand grenade that exploded under a Volkswagen parked near the embassy, he said.
When the gunfire died down, the guerrillas calmly walked down the street, piled into two cars and fled, said Dr. Oscar Duras, who was watching from his office less than 50 feet away.
Lane's official communique said the assault was 'the fourth attack in three weeks.' The four included a previously unreported incident this month in which embassy sources said 'two or three shots' were fired at the building.
In other attacks, presumed rightists fired on the mission March 4 and suspected leftists fired on it March 17. No injuries were reported in the other attacks.