A car bomb explosion today demolished a three-story building used by Palestinian guerrillas and Syrian officers in Lebanon's eastern Bekaa Valley, about 30 miles east of the capital.

The Lebanese Civil Defense said tonight that rescue teams at the site had reported recovering 30 bodies from the rubble. The rescuers had also pulled out four survivors and said that the cries of other survivors could be heard in the debris. The Civil Defense office said that 15 persons had been injured in the blast at the building on a main highway near the town of Shtawrah near the Syrian border.

There was no reliable indication tonight on who was responsible.

Police here said they had received information that the blast came from a car parked in an underground garage that was rigged with 331 pounds of explosives. It touched off a chain of other explosions in the basement, which was also used as an ammunitions depot, police said.

The building was a headquarters in the Syrian-controlled section of eastern Lebanon for the Palestine Liberation Organization's Fatah faction and it contained offices occupied by some Syrian officers and other PLO groups.

[Associated Press reported that a bomb exploded late Friday at a shoe shop in West Beirut's Hamra shopping thoroughfare and witnesses said at least five people were wounded. There was no immediate claim of responsibility.]