At least seven Guinean schoolgirls drowned Sunday after a pirogue -- a long wooden vessel -- they were travelling in capsized, the education minister said.

The girls were crossing the Niger river in the northeast of Guinea in West Africa to take high school entrance exams that begin on Monday.

"We are struck by this bad news that seven students lost their lives," the minister for literacy and pre-university education, Guillame Hawing, told journalists on a visit to the region to launch the exam period.

Mamadi Keita, a security officer, told AFP his half-sister was among those who died.

"She and her classmates went to the other side of the Niger river for the first tests for their entry exam into their seventh year" of school.

"They boarded an overloaded pirogue which sank under the weight of passengers and goods," he said in tears over the telephone.

A local source, speaking on condition of anonymity, told AFP the death toll was provisional, and that the search for more bodies was still underway.