AL-ARISH: Unidentified gunmen shot at an Egyptian security checkpoint in the Sinai region, scene of an army offensive against Islamist militants, early on Sunday, Egyptian and international officials said.

But an official for the Sinai international peacekeeping force, which helps maintain the peace accord between Israel and Egypt, denied that its own troops had come under fire.

An Egyptian official had said gunmen opened fire on the peacekeeping troops in the Um Shyhan area of central Sinai, without causing any injuries, after shooting at a police checkpoint and clashing with Egyptian security forces.

"We were not fired upon," said Kathleen Riley, Cairo representative of the Multinational Force and Observers (MFO) which has monitored movements of troops and military equipment along Egypt's border with Israel since their 1979 peace treaty.

"There was some firing on an Egyptian army checkpoint or police checkpoint not too far away. We were able to hear the shots but we had absolutely no attacks upon our staff."

The incident follows the start of an Egyptian operation targeting Islamist militants in Sinai suspected of killing 16 border guards a week ago.

The government in Cairo has sent armoured vehicles and hundreds of troops in the biggest build-up in the treaty's demilitarised zone since Egypt's 1973 war with Israel. AGENCIES