At least 10 others were injured in the attack near Fort Portal by rebels of the Allied Democratic Front.

Witnesses said about 80 rebels overpowered an army unit before attacking the school, setting dormitories on fire when the students refused to come out.

Many of the boys inside were burned to death.

About 100 students were unaccounted for by Monday evening, and there are fears that they may have been abducted by the rebels, who have in the past kidnapped young men to bolster their forces.

A BBC correspondent in Uganda says it is the worst such attack since the ADF began their rebellion against the government of President Museveni in late 1996.