Kinshasa – More than 70 inmates broke out of a prison in southwestern Democratic Republic of Congo on Friday, a local activist and a national deputy said, two days after thousands escaped from the capital's main penitentiary.

Prison breaks are relatively common in Congo, but the latest series of large-scale escapes points to deepening disorder in the wake of President Joseph Kabila's refusal to step down from power after his mandate ended in December.

Kabila's decision to remain in power beyond his mandate has fuelled deadly street protests and a surge in militia violence, raising fears of a backslide to the civil wars at the turn of the century that killed millions.

Valentin Vangi, president of the Civil Society of Kongo Central province, said that 73 of 77 prisoners at the prison in the town of Kasangulu escaped around 2 am (0100 GMT).

"The criminals climbed the wall," Vangi told Reuters. "When the guard went to inform the police, he left the door open, which allowed them to escape."