Militants attacked Egypt's security forces and wounded four policemen in the Sinai peninsula on Saturday, in the tenth day of clashes since 16 soldiers were killed in the volatile borderland near Israel and the Gaza strip earlier this month.

The troops were returning from an early morning raid where they had arrested two suspects in their homes when militants fired a rocket-propelled grenade at their convoy as it was driving along a major road, a security official said.

The government troops fired back immediately but the attackers fled, the official added, speaking on condition of anonymity because he was not authorized to speak to the press. The attack occurred on the coastal road linking northern Sinai's main city of el-Arish to the Egypt-Gaza border town of Rafah.

Senior security officials say Islamic militants were behind the Aug. 5 assault on the soldiers, the worst attack on troops from inside Egypt in living memory. They died when masked gunmen stormed their security checkpoint, mowing them down as they broke fast for the Muslim holy month of Ramadan.

The attackers then stole an armored vehicle and stormed across the border into Israel, where an Israeli airstrike stopped them in their tracks, killing six.

Large swaths of northern Sinai have plunged into lawlessness following Mubarak's ouster, and weapons smuggled from Libya have found their way into militants' hands. The weapons and the security vacuum have fueled the rise of al-Qaida-inspired militant groups, which have staged several low-level cross-border attacks on Israel.

The attacks prompted the military to launch an offensive in the increasingly unstable peninsula. Most operations there however remain limited and the objectives are unclear. However, for the first time since Egypt signed a peace deal with Israel, military helicopters, tanks and troops have been deployed there — a move which before had not been allowed under the deal.

The killings also sped up a military and security shake-up in Cairo, as Islamist President Mohammed Morsi ordered the longtime defense minister and a number of the former ruling military council into retirement, dismissing Egypt's intelligence chief as well.

On Wednesday, Islamic militants put out a statement warning the military against cracking down on jihadists, claiming they were not behind the Aug. 5 sneak attack on the soldiers, which authorities have cast as a national tragedy.

In a statement posted on a website which usually carries statements by al-Qaida and similar groups, the militants said they focus mainly on Israel and do not target Egyptians soldiers. There was no way to independently verify the claim.

"Prevent bloodshed, blood which has been spilled and which will be spilled if this aggression continues. You are dragging us to a battle that is not ours," the statement read.