CAIRO (Reuters) - Air strikes in northern Sinai have killed 19 members of Egypt’s Islamic State affiliate, including three of its leaders, the Egyptian military said on Thursday.

Islamic State this week claimed an attack on security forces near St. Catherine’s Monastery in the south Sinai, the latest incident in a spate of Islamist violence targeting Egypt’s Christian minority in recent months.

Egypt is tightening security ahead of a visit by Pope Francis next week as a result of suicide bombings this month on two Christian churches, also claimed by Islamic State, that marked one of the bloodiest days for the country’s Christians in decades.

In a statement on its official Facebook page, the military said the air strikes were directed at militants in Ansar Bayt al-Maqdis, which pledged allegiance to Islamic State in 2014 and adopted the name Sinai Province. Officials have blamed the group for killing hundreds of Egyptian soldiers and police since then.

The military did not name the leaders it had killed in the strikes, but described one as among the group’s most prominent members, and another as the head of its sharia law committee. The third was an official in charge of interrogations.

There was no immediate comment from Islamic State on the air strikes.

Egypt has for years been battling an Islamist insurgency in the northern Sinai, which gathered pace after the military overthrew President Mohamed Mursi of the Muslim Brotherhood in 2013 following mass protests.