Egypt has decided to tighten security measures in the north of its Sinai Peninsula over fears of terrorist attacks after upholding death sentences for Islamist militants, Egyptian media reported on Wednesday.

Troops have been put on high combat alert, guard of police stations has been reinforced, and additional armored personnel carriers and tanks have been brought into al-Arish, the capital of the Egyptian governorate of North Sinai as intelligence was received that militants may stage acts of retribution.

On Monday, an Egyptian court upheld death sentences for 14 Islamist militants over last year’s attacks on a police station and a bank office in the Sinai Peninsula, when about ten people, mainly police officers, were killed in al-Arish.

An army operation against extremist groups is currently underway in Sinai. It is a response to an armed attack by extremists on an Egyptian border checkpoint in August that left 16 Egyptian servicemen dead.