People are seen outside the Mar Mina Church after a blast, in Helwan district on the outskirts of Cairo, Egypt after a blast December 29, 2017 Reuters

Egyptian security members and forensic police inspect the site of a gun attack outside a church south of the capital Cairo, on December 29, 2017 (Photo: AFP)

People gather at the site of attack on a church in the Helwan district south of Cairo, Egypt December 29, 2017 Reuters

People are seen outside the Mar Mina Church after a blast, in Helwan district on the outskirts of Cairo, Egypt December 29, 2017 Reuters

Security forces stand guard at the site of attack on a church in the Helwan district south of Cairo, Egypt December 29, 2017 Reuters

People stand behind police tape cordon at the site of attack on a church in the Helwan district south of Cairo, Egypt December 29, 2017 Reuters

A priest reacts at the site of attack on a church in the Helwan district south of Cairo, Egypt December 29, 2017 Reuters

Security forces stand guard at the site of attack on a church in the Helwan district south of Cairo, Egypt December 29, 2017 Reuters

An Egyptian woman stands next to a cordoned off bullet-riddled wall at the site of a gun attack at a church south of the capital Cairo, on December 29, 2017 AFP

People gather at the site of attack on a church in the Helwan district south of Cairo, Egypt December 29, 2017 Reuters

Bullets holes are seen on the police booth outside Mar Mina church, in Helwan, Cairo, Egypt, Friday, Dec. 29, 2017 AP