A bomb exploded in a crowded departure lounge at Frankfurt's international airport today, killing three persons and wounding at least 28, according to West German police.

Police investigators in Frankfurt said there were no claims of responsibility, nor did they immediately discover any solid clues in the wreckage indicating who could have planted the bomb.

The explosives were placed in a wastepaper basket in the international departure lounge close to the desk of Italy's Alitalia Airlines. But the ticket counters of several other foreign airlines also are located nearby so it was difficult to determine which, if any, of them was the target, police said.

The blast tore a hole three feet deep in the concrete floor and devastated many airline counters. Two of those killed were children, the other an adult male. All were passengers but they could not be identified immediately because the bodies were so badly mutilated, according to police spokesman Kurt Kraus.

Hans-Joachim Borst, a member of the airport's management committee, said four of the wounded, including a child, were in serious condition.

The explosion took place in the middle of the afternoon beyond the security zone where baggage is inspected. There was no warning given beforehand to allow for the evacuation of passengers, the police officials added.

It was the worst attack at the vast Rhein-Main airport, which serves as an important connecting center for international flights. Although security is relatively tight, previous terrorist incidents have taken place there, but they never resulted in deaths.

The bomb blast, which occurred as the noontime air traffic "rush hour" was easing, left a wide area littered with ripped baggage, broken glass and small fires. A full-size replica of a Red Cross plane suspended from the ceiling as part of an exhibition caught fire and fell from its moorings.

A British passenger, Alec Ballantine, who was returning to his home in Edinburgh with his wife, said: "All we heard was a bang and we saw two flashes. One of the airplanes attached to the ceiling collapsed and we got blown off our seats."

Frankfurt police president Karl-Heinz Gemmer said at a press conference that the force of the blast was so great "the explosives must have weighed several kilos." He said he based his estimate on the extent of damage to the departure lounge, not on analysis of the bomb fragments.

Shortly after the Frankfurt explosion, a travel agency at the Munich train station received a telephone call warning that a bomb would soon explode in the departure hall of the local airport. Police protectively evacuated and then sealed off the departure building at Munich's airport.

Later, when no blast occurred, Munich police officials surmised that the threat was probably a hoax by someone who had heard about the Frankfurt bomb.