An Egyptian military official says three soldiers have been killed by a roadside bomb in the northeast of the Sinai Peninsula.

The official says the blast early Monday happened near a checkpoint close to the village of el-Kharouba as the soldiers' vehicle passed by. He says a fourth soldier is in serious condition and has been transferred to a hospital.

The official spoke on condition of anonymity because he was not authorized to speak to journalists.

Sinai has been rocked by series of suicide bombings and attacks mainly targeting police, soldiers and tribesmen suspected of having links to security agencies.

A group called Ansar Beit al-Maqdis — which has claimed responsibility for most of the attacks — has pledged allegiance to the extremist Islamic State group.