"I feel moral and political responsibility that we failed to eradicate the horrible practice (of torture)," Bacho Akhalaia said in comments published by the interior ministry website.

"This is why I have submitted my resignation to the president."

Before taking up his post as interior minister, Akhalaia previously oversaw the country's prisons.

The videos of abuse shocked the nation and drew international condemnation before crucial elections and protesters across the country had called for Akhalaia's resignation.

Some of the graphic video footage showed a weeping, half-naked male prisoner at a jail in Tbilisi begging for mercy before apparently being raped with a stick, while other images showed prison guards brutally kicking an inmate.

Several thousand people demonstrated for a second day Thursday in the cities of Tbilisi, Batumi and Rustavi in protest at the revelations.