Egyptian police have killed 19 gunmen involved in an ambush that killed seven Coptic Christians south of Cairo two days ago, the interior ministry said.

Security forces tracked the "terrorists" who belong to a cell that carried out the attack to a hideout in a mountainous region west of Minya governorate, where Friday's attack took place, the ministry said in a statement published on its official Facebook page on Sunday.

The men were killed in a shootout after they opened fire on security forces as they approached them, the statement added.

The ministry published photos of bloodied bodies with their faces concealed and assault rifles and shotguns lying beside them.

Gunmen on Friday opened fire on two buses carrying Christians near the Monastery of St Samuel the Confessor in Minya, some 260 km south of Cairo, killing seven and wounding 18 others. Six of those killed were of the same family.

The attack, the latest in a series of assaults targeting the country's Christian minority, was claimed by the Islamic State group, according to the group’s Amaq news agency.

The group was also behind another attack that killed 28 people in almost the same spot in May 2017.

Christians make up around 10 percent of Egypt's 97 million predominantly Muslim population.