GENEVA (AP) _ Explosions damaged six trucks loaded with U.N. relief supplies for Kurdish northern Iraq, a U.N. official said Monday. No injuries were reported.

The U.S.-donated wheat and flour on two of the trucks were destroyed in the explosions late Sunday in Irbil, Iraq, said the official, who spoke on condition he not be identified.

The Iraqi Kurdistan Front issued a statement in Washington, D.C., that Turkish drivers from the convoy said they had been stopped at Iraqi checkpoints on their way to Irbil and were taken away for questioning by Iraqi officials.

The front, an umbrella organization of seven major Kurdish political parties, said the drivers suspected that time bombs were attached to trucks while they were being questioned.

The U.N. official in Geneva refused to speculate on this report. He said U.N. guards in the protected zone of northern Iraq were investigating.

The trucks were part of a 25-truck convoy that brought the food aid from Turkey during the weekend and were in a CARE warehouse in Irbil, about 200 miles north of Baghdad, when the explosions occurred, the U.N. official said.

The trucks, only the second convoy to bring aid to the Kurds this winter, passed through checkpoints in territory controlled by Iraqi forces on the way to Irbil, the capital of the self-proclaimed autonomous Kurdish republic in Iraq, the official said.

A new convoy of 24 trucks was underway on Monday with more wheat and flour from the $150 million U.N. aid program program, the official said.

Iraqi officials have blocked food and fuel shipments to the three northern Kurdish provinces of Iraq, where 3.5 million Kurds live.

The new aid effort follows months of impasse between the United Nations and Iraq over assistance to the Kurds. It started after an Oct. 22 agreement between the United Nations and Baghdad.

A London-based representative of the Iraqi Kurdish guerrilla movement Patriotic Union of Kurdistan said in a telephone interview that the explosions were an Iraqi attempt to disrupt the relief operation.

Latif Rashid said Iraqi authorities have access to the trucks because Baghdad insisted that the aid pass through Iraqi-held territory instead of going directly from Turkey into the U.N.-protected Kurdish area.