An Egyptian appeals court overturned on Wednesday death sentences for 149 pro-Muslim Brotherhood accused of killing policemen in a mob attack on their station.

An Egyptian appeals court overturned on Wednesday death sentences for 149 pro-Muslim Brotherhood accused of killing policemen in a mob attack on their station, a judicial source said.

The court ordered a retrial for the defendants over the attack, which killed 13 policemen near Cairo on August 14, 2013, the day police shot dead hundreds of MB demonstrators in the capital.

The initial ruling in February 2015 came amid a series of death sentences in mass trials that were criticized internationally, as the government cracked down on supporters of ousted MB president Mohammad Mursi.

The court had also sentenced 37 people to death in absentia, but they would have to hand themselves in for a retrial.

The grounds for the appeals court ruling were not immediately available, but the court has overturned hundreds of death sentences over the past year, to the relief of rights advocates and frustration of some in the government who have urged fast track executions.

Seven people have been executed for political violence since Mursi's ouster, including six who were convicted of belonging to a militant group.