A suicide bomber rammed his car into an army checkpoint in Egypt’s restive Sinai Peninsula on Thursday, killing four soldiers, according to security officials.

A suicide bomber rammed his car into an army checkpoint in Egypt's restive Sinai Peninsula on Thursday, killing four soldiers, according to security officials.

Another three soldiers were wounded in the attack on the Al-Reesa checkpoint just south of North Sinai's main town of El-Arish, the officials said.

Attacks on the army and police have increased since the army's July 3 ouster of Islamist president Mohammad Mursi and a subsequent crackdown on his supporters and members of his Muslim Brotherhood.

Militants have launched a series of brazen attacks this week, after at least 57 people were killed in clashes between security forces and Mursi supporters on Sunday, most of them in Cairo.

On Monday, three people were killed and around 50 wounded when a car bomb exploded outside a security building in Al-Tur, the capital of South Sinai.

In the Suez Canal city of Ismailiya, gunmen killed six soldiers in an attack on an army patrol.

And in Cairo, unknown assailants fired rocket-propelled grenades at communication satellite dishes, damaging one.