CAIRO, Egypt — Unidentified gunmen attacked an Egyptian police convoy near the main ring road around Cairo, killing three officers and wounding five others, the interior ministry said early on Tuesday.

“Armed elements riding in two vehicles approached a moving security convoy” around 11:45 p.m. Monday, the ministry said in a statement.

The convoy was crossing a roundabout that intersects with the main ring road that surrounds the capital, separating New Cairo and newer real estate projects from the city.

Police returned fire at the attackers’ vehicles, which police were pursuing “in an effort to apprehend the perpetrators,” the ministry said.

While no one claimed responsibility for the attack, Egypt has been fighting an insurgency by a local affiliate of the Islamic State group in North Sinai province.

Hundreds of soldiers and policemen have been killed in the insurgency since the army overthrew Islamist president Mohamed Morsi in 2013.

Following deadly church bombings last month, President Abdel Fattah el-Sissi declared a three-month state of emergency on April 10.

IS said it was behind the church bombings in Tanta and Alexandria on April 9 that killed 45 people.

The military has killed several of the group’s top leaders, but the jihadists have increasingly expanded their attacks from Sinai to other parts of Egypt, including Cairo.