July 20 (UPI) -- A ferry carrying 133 passengers and crew members capsized off the coast of Guyana, where authorities continued searching Monday for dozens of missing people while investigating possible irregularities in the vessel's operation.

The MV Barima departed Georgetown on Saturday afternoon bound for Port Kaituma, a remote community in the country's northwest that is primarily accessible by sea and river.

According to the official manifest, the vessel was carrying 116 passengers, 17 crew members and some 268 tons of cargo when it issued a distress signal about 11 p.m., Prime Minister Mark Phillips said.

By midday Sunday, rescue teams had saved 67 people, including 41 men, 11 women and 15 children, while the search continued across an area expanded to more than 385 square miles with support from the Guyana Defence Force, the Coast Guard, other government agencies and local fishermen, according to the government.

As rescue efforts progressed, authorities discovered several of the people found alive were not listed on the ferry's official manifest.