Cairo, Sep 2 (IANS): At least 11 Egyptian policemen were killed Tuesday in an explosion in North Sinai's Rafah city, a security official said.

The blast occurred when a police vehicle went over a planted explosive device in Rafah city's Wefaq village, the same village where eight extremists, including the head of the Sinai-based Ansar Bayt al-Maqdis group, were killed in a military raid Sunday, the official told Xinhua.

Four other security personnel were seriously wounded in the attack.

Following the blast, militants exchanged fire with the police, and a status of high alert was declared, official news agency MENA reported, adding the death toll might increase.

In July, over 50 extremists were killed in military raids in response to the killing of police and military officers by gunmen.

Militant attacks, which usually target security personnel but also lead to civilian casualties, have surged since the ouster of Islamist president Mohamed Morsi in July last year.

Sinai-based Al Qaeda offshoot Ansar Bayt al-Maqdis has claimed responsibility for most of the attacks against the security personnel.