CAIRO Three Egyptian policemen were killed on Monday when masked men attacked a checkpoint in the Nile Delta city of Mansoura, security sources said.
No group has claimed responsibility for the attack. Al Qaeda-linked Islamist militants have stepped up attacks on soldiers and police since the army toppled Islamist President Mohamed Mursi in July.
The majority of the attacks have been carried out in the largely lawless Sinai region, although militants have on occasion extended their campaign into major cities.
Three men in a car and one on a motorcycle approached the checkpoint before dawn and fired at the policemen "to make sure that they were dead", a security source in Mansoura said, speaking on condition of anonymity.
"This is another attack in the series of terrorist attacks against the police," he said, saying the violence shows the intent of "revenge" against the security forces. He did not specify who had carried out the attack.
State-run newspaper Al-Ahram reported that 60 bullet casings were found at the site of the attack.
The police were conducting search operations to locate the perpetrators, but no arrests had been made, according to an emailed statement from the interior ministry.
The army-backed interim government says it is fighting a war on terror, and makes no distinction between the Sinai-based militants it calls "terrorists" and ousted president Mursi's Muslim Brotherhood.
Since Mursi's ouster, the state has launched a fierce security crackdown on the Brotherhood, killing hundreds of members, arresting more than two thousand, and banning the movement.
The Brotherhood, Egypt's oldest and biggest Islamist group, denies any links with militant activity.
(Reporting By Maggie Fick, editing by Elizabeth Piper)