A boat ferrying passengers to a traditional festival overturned off the coast of Djibouti Thursday, killing at least 69 people, an official said.

More people were feared missing or dead, said Ismael Tani, an adviser to Djiboutian President Ismail Umar Guelleh, said by telephone.

"There were many dead," he said, adding that 69 was the provisional death toll. He said it overturned in the harbor after leaving port about noon and "was probably overloaded."

Tani said officials believed more than 200 people were on board the vessel, which he said was headed for a traditional fair.

A U.S. public affairs officer from the Combined Joint Task Force-Horn of Africa, based in Djibouti, said the U.S. had offered assistance to the government.

"They asked us if we had any divers who could provide assistance," said Capt. Bob Everdeen. He said U.S. divers reported to the Djiboutian navy headquarters.

Djibouti, a Horn of Africa nation of some 486,000 people bordering Eritrea, Ethiopia and Somalia, is a former French territory and hosts the only U.S. military base in sub-Saharan Africa.

The tragedy came nearly two months after 10 U.S. members of the counterterrorism force died when a pair of Marine Corps helicopters crashed in the Gulf of Aden, near the northern coastal town of Ras Siyyan in Djibouti.

The impoverished region is home to a sizable Muslim population. U.S. officials say it has been used by terrorists as a place to hide, recruit operatives and stage attacks.