Eleven Egyptian policemen were killed when a roadside bomb blast struck their armoured vehicle in the restive Sinai Peninsula on Tuesday, security officials said.
Militants have claimed a string of attacks that have killed scores of policemen and soldiers, mostly in north Sinai, since the army overthrew president Mohamed Morsi in July last year.
Another four conscripts were wounded in the explosion on a road leading to the town of Rafah bordering the Palestinian Gaza Strip.
The military has sought to quell the militants in a massive operation that has killed scores of extremists and netted some of their leaders.
The main militant group, Ansar Beit al-Maqdis, has acknowledged in statements the loss of some of its leaders, but has continued to attack both the security forces and Bedouin suspected of collaborating with them.
The group, whose name means Partisans of Jerusalem, has also said it was behind deadly bombings of police buildings in the capital and the Nile Delta.