Syrian rebels have seized the Aleppo central prison, freeing hundreds of prisoners on Thursday, according to multiple news reports and rebel sources.

The rebels took control of 80% of the estimated 4,000-person Assad-run prison complex, said Rami Abdel Rahman, a spokesman for the Syrian Observatory for Human Rights. The groups behind the assault, Rahman told French news agency Agence France-Presse, were Ahrar al-Sham and Al-Nusra, a jihadist group.

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Syrian state television was quick to deny the news, broadcasting a breaking news alert stating that soldiers and security forces had foiled an attack against the prison "by terrorist groups," according to Sky News.

Al-Nusra, one of the groups reportedly involved in the capture, tweeted about the assault, asking people to pray until they can liberate the entire prison, according to two different translations. While reports state "hundreds" have been freed thus far, the numbers are continuing to grow.

#جبهة_النصرة ترجو من الجميع اللجوء إلى الله بالدعاء أن يفتح على المجاهدين داخل #سجن_حلب_المركزي حتى يتم النصر ويتحرر كامل السجن بإذن الله — جبهة النصرة (@JabhtAnNusrah) February 6, 2014

Rebels have been trying to attack the prison for months. The assault was part of a vast military operation announced on Thursday by a Syrian rebel coalition. The operation was dubbed "Truthful Promise Approaches" by the Islamic Front and Al-Nusra, as reported by Al Arabiya.

The rebels' partial victory on Thursday comes after two months of relentless air strikes ordered by President Bashar al-Assad. Just in the last five days, the campaign has taken the lives of 246 people, including 73 children, according to the Syrian Observatory for Human Rights.

Sayfullah as-Shishani, one of the leaders of Al-Nusra, was reportedly killed during the attack, according to multiple news reports. Al Mayadeen, a Lebanese Arabic-language news station, posted a purported picture of as-Shishani on Facebook.