Gunmen shot and killed an Egyptian police officer during an ambush Saturday in the Sinai peninsula, a security source said, the second attack on police in the restive region this month.

"Colonel Mohammed Hani, a high-ranking officer, was killed by six bullets to the head when unknown gunmen opened fire on him with machine guns," the source said.

The gunmen were in a car that was used to ambush the officer in a street of the Sinai town of El-Arish, he said.

Another security source blamed the attack on Islamist militants and said it was the second one in a month targeting the police in the Sinai.

Three weeks ago, armed men shot dead police officer Mohammed Abu Shaqra who served in the anti-terrorism squad at El-Arish.

A hive of militant activity, Egypt's Sinai peninsula is a major route for drugs smuggling and human trafficking.

Ever since the uprising that ousted Hosni Mubarak in 2011, throwing his feared security services into disarray, the region has grown even more restless and awash with weapons.

Attacks on police and soldiers, and abductions of tourists, in the sparsely populated peninsula have surged since Mubarak's overthrow as have cross-border attacks on Israel.

In August 2012, suspected Islamist gunmen killed 16 Egyptian soldiers near Israel's border and commandeered an armoured vehicle into Israel, where they were stopped by a helicopter strike.

Bedouin activists who populate the Sinai have long complained of the government's neglect of the region, saying they have been treated as second-class citizens ever since Israel handed back the peninsula it had seized in the 1967 Six-Day War.