A ferry has capsized in the southern African country of Zambia, leaving at least 26 people dead, most of them children, officials have said.

Authorities said on Saturday that 23 school children, aged between six and 15 years, a baby and parents drowned.

The children were travelling to another school across Lake Kariba, in the south of the country, where they were meant to participate in Zambia's 50th independence day celebrations.

Zambia's vice president, Guy Scott, visited the area on Saturday and said the government would cover funeral expenses.

"The death of these people is disheartening, more so that they were travelling for a national cause. They are true heroes,'' Dr Joseph Katema, a government spokesman, said on Saturday.

The accident was caused by overloading, according to authorities, with the boat carrying 20 people more than its capacity allowed.

Rescue operations were under way with military and police divers sent to the lake to retrieve the bodies.

Source: Agencies