An Egyptian court on Monday confirmed death sentences against 183 men convicted of killing 13 policemen in a town near Cairo in August 2013.

The court had in December issued a preliminary verdict against 188 defendants in a mass trial, of whom two were acquitted on Monday while one, a minor, was sentenced to 10 years in prison.

Charges against the remaining two were dropped after the court found that they were dead.

Monday's verdict, which can be appealed, came after the initial sentences were sent to the grand mufti, the government's official interpreter of Islamic law, for ratification.

The accused, of whom 143 are behind bars, were found guilty of taking part in an August 14, 2013 attack on a police station in Kerdasa, a village on the outskirts of Cairo, in which the 13 policemen were killed.

The attack took place on the same day that security forces killed hundreds of demonstrators in clashes as they dismantled two massive protest camps in Cairo supporting ousted president Mohamed Morsi.

Since the army deposed Morsi on July 3, 2103, at least 1,400 people have been killed in a police crackdown on protests. mostly Islamists supporting the ousted leader.

Hundreds of his supporters have been sentenced to death in swift mass trials which the United Nations says were "unprecedented in recent history".

On Monday, an appeals court ordered a retrial in a separate case involving the killing of a police major general in a firefight in Kerdasa.

Major General Nabil Faraj was killed on September 19, 2013 when security forces stormed Kerdasa to flush out Islamist supporters of Morsi,

Islamists had taken control of the village soon after police launched the brutal crackdown on Morsi's supporters in the two Cairo squares.

In August 2014, a lower court had confirmed death sentences on 12 of the 23 defendants tried on charges of killing Faraj.

Seven of those sentenced to death are in custody, and five are on the run. Ten other accused were sentenced to life imprisonment, while another defendant was acquitted.

On Monday, the Court of Cassation ordered a retrial for seven of the 12 who were sentenced to death and four of the 10 sentenced to life in prison. The other defendants are on the run.