At least nine policemen have been killed in a bomb attack on a convoy in Egypt's Sinai Peninsula, officials said, according to BBC News.

The bomb was reportedly detonated remotely as they travelled through the village of Wefaq, near the Gaza border.

Security forces have been carrying out an offensive in northern Sinai, killing and capturing dozens of suspected members of jihadist militant groups. Militants have stepped up attacks on soldiers and police since the overthrow of President Mohammed Morsi last year.

The main Sinai-based jihadist group, Ansar Beit al-Maqdis, has acknowledged in statements that several of its leaders have been killed in the recent security operation.

Last week, it also announced that it had beheaded four Egyptian civilians whose bodies were found in August. It accused them of providing Israel with intelligence for an air strike that killed three of its fighters in late July.

A video published online showed armed, masked men standing over four captives as a statement was read out. They were then decapitated.

The footage was reminiscent of videos of killings posted by Islamic State (IS), a jihadist group that has taken control of large swathes of Iraq and Syria. However, Ansar Beit al-Maqdis is not believed to be linked to IS.