But one former official said that the exact provenance of the arms that were being smuggled via Sudan was unclear.

Although the airstrike was carried out two months ago, it was not publicized until Sudanese officials said Thursday that a convoy of trucks in the remote eastern part of Sudan was bombed by what they called “American fighters,” killing dozens. The strikes were first reported on several Internet-based news sites, including cbsnews.com.

The area where the Sudanese said the attack occurred, near Port Sudan on the Red Sea, is an isolated patch of eastern Sudan near the Egyptian border and a notorious smuggling route, populated mostly by nomads and known as one of the poorest, least developed parts of a very poor, underdeveloped country.

The Sudanese said the reports emerged now because it took time to fully investigate the strike. But an accusation from one government official that the attack was an American act of genocide raised the possibility that the Sudanese were lashing out because the International Criminal Court had issued a warrant for the arrest of their president, Omar Hassan al-Bashir, on war-crimes charges in the conflict in Darfur.

The official, Rabie A. Atti, a government spokesman, also gave a death toll in the attack that was higher than the 39 reported in other secondhand accounts. Mr. Rabie said by telephone from Khartoum, the capital, that “more than 100 people” had been killed in the air raid. He said the trucks that were bombed were not carrying weapons. “I’ve heard this allegation, but it’s not true,” he said. “It was a genocide, committed by U.S. forces.”