There’s going to be some serious blowback from Obama’s Libyan adventure.

Tripoli, Libya (CNN) — Hundreds of Islamist militants were among the prisoners freed from a notorious Tripoli prison this week, according to a former Libyan jihadist.

The freed militants had been imprisoned in Tripoli’s Abu Salim prison by Moammar Gadhafi’s regime during the height of the insurgency in Iraq, according to Noman Benotman, once a senior figure in the Libyan Islamic Fighting Group. Benotman said he believes as many as 600 militants may have been among the prison population at Abu Salim.

It’s not known how many prisoners were held in the vast facility. Human Rights Watch said Gadhafi’s prisons “have been filled to the limit in the last few months with thousands of people who were arrested for taking part in the anti-Gadhafi protests, or because of their suspected support for Libya’s democratic opposition.”

The human rights group, which recently had a team visit the prison, estimates that before the uprising, there were a few hundred Islamists held at Abu Salim.

Benotman, now a senior analyst at the Quilliam Foundation in London, said the freed prisoners are Salafists, embracing a puritanical interpretation of Islam that has gained ground in Libya in recent years.

Gadhafi’s regime imprisoned thousands of suspected pro-al Qaeda militants after the 2003 U.S. invasion of Iraq stoked radicalization in Libya, especially in its impoverished eastern provinces. According to Benotman, those rounded up by the regime included militants who had tried to travel to Iraq and some who had returned from fighting against U.S. forces there. He said many of them had already been released by the Gadhafi regime.

Wednesday’s prison release, which occurred as rebel forces took control of the Abu Salim area of Tripoli, comes as Islamists are taking on an increasingly prominent role in the fight against the Gadhafi regime — to the concern of some in the West.

Former members of the Libyan Islamic Fighting Group (LIFG) have assumed leadership positions in several rebel brigades, according to Benotman. Their current prominence, he said, was due to their quick mobilization — as armed opposition replaced peaceful protests in Libya — and their valued military skills.