(AP Photo/Hussein Tallal)

By MOLLY HUNTER and ADAM MAKARY

CAIRO - Hours after Egyptian army chief General Abdel Fattah El Sissi urged the Muslim Brotherhood to pursue dialogue instead of "terrorism," at least 38 Brotherhood prisoners have been shot dead by security forces in Cairo.

The Anti-Coup Alliance said in a statement that it had "received with horror and great sadness the news of the killing of 52 detained anti-coup protestors, with 25 others in critical condition." The group said the detainees were killed while being transferred to Abu Zaabal prison. The group has since released a list of 52 names of the dead.

Egypt's interior ministry said one of the prisoners tried to take a police officer hostage, prompting the security forces to respond with tear gas. In a statement, the ministry said at least 38 Morsi supporters in the security van died of tear gas inhalation, while state TV put the number at 36.

The prisoners had all been detained after clashes Saturday at Cairo's Al-Fateh mosque, the site of an hours-long stand-off between security forces and anti-military protesters.

Egypt's state news agency MENA reported the vehicle was in a convoy of vans transporting more than 600 detainees to the prison some 40 miles outside the capital. During the 2011 revolution, prisoners, including hundreds of Brotherhood members, staged a mass jail break at the Abu Zabaal prison.

As the death toll climbs by the day, the Brotherhood finds itself in an increasingly perilous political position. In the last 36 hours, more than 1,200 Brotherhood supporters have been detained or arrested and many rounded up after Friday's "Day of Rage" face accusations of vandalism and murder.

Most of the senior Brotherhood leadership is currently being held incommunicado, including former Egyptian President Mohamed Morsi, and today dozens more leaders were reportedly detained in raids.

It's an all too familiar position for the group that was founded in 1928 and first banned in 1954 by strongman General Gamal Abdel Nasser. On Saturday, a government spokesman announced the beginning of formal deliberations about the group's political future and today the interior ministry submitted a formal proposal to ban the group.