STONE TOWN, Zanzibar: Rescue workers fought rough seas on Thursday to search for survivors after an overcrowded ferry sank near the Indian Ocean archipelago of Zanzibar, but hopes of finding people alive were slim.

At least 68 people were confirmed dead and 145 were rescued after the MV Skagit/Kalama capsized around midday on Wednesday near Chumbe island, west of Zanzibar.

The vessel had set sail from mainland Tanzania to the semi-autonomous archipelago, a popular tourist beach destination. One U.S. citizen was among the dead.

Hundreds of people gathered at the Maisara Grounds park near Zanzibar's historic Stone Town area on Thursday to identify bodies laid out in a tent.

Tatu Kwiyela, a 35-year-old woman from mainland Tanzania, survived the accident but her nine-month-old son died.

"I was swept away by strong waves and lost my son, Saidi Jumanne. I tried to hang on to him but he disappeared into the sea," said Tatu, who managed to identify his remains.

Police said more than 10 foreign tourists, including a group of Dutch holidaymakers, were among the rescued passengers.

"One of those killed in the ferry accident is an American citizen. The body has been recovered and is being preserved at a mortuary," Zanzibar police spokesman Mohammed Mhina said.

The ferry, with a maximum carrying capacity of 250 people according to Zanzibar marine authorities, was carrying 290 people, officials said.

"Out of the 68 dead victims, 54 bodies have been identified so far by their relatives and taken for burial," Mhina said.

"We will continue with the search and rescue operation tomorrow morning, although it is becoming increasingly difficult to find any survivors now."

There were at least 145 survivors.

Rescue teams battled heavy winds and rough seas in their search effort. Divers trying to pluck more bodies from the wreckage said they were not able to reach the vessel.

"The sunken boat is below depths of 25 meters (82 ft) ... we tried to go as deep as we could but could not locate it," Ali Ramadhani, one of the divers, said.

"All we've seen today are bodies floating in the sea. I don't think we are going to find anyone alive. The sea is very rough, it is difficult for anyone to survive in such conditions."

Some of the victims' relatives said they were angry at authorities for lax safety regulations, especially after more than 200 people were killed in a ferry accident in September in Zanzibar's worst maritime disaster.

"The government has killed all these people. They must bring the owner of the boat to us," said Abdallah Sadick whose brother was among the missing passengers.

Zanzibar residents said passenger ships are notoriously overcrowded and there are few safety inspections.

Tanzanian President Jakaya Kikwete ordered an investigation into the incident and announced three days of national mourning.