European Commissioner for European Neighbourhood Policy and Enlargement Negotiations Johannes Hahn firmly condemned Friday's terrorist attack on a Coptic church in south Cairo, which left nine killed and five injured.

"Firmly condemn yet another heinous terror attack on #Coptic #Christians in #Egypt," Hahn wrote on his Twitter account.

"My sincerest condolences to the families of the victims. #EU stands by #Egypt and all its people," Hahn added.

On Friday, two unidentified gunmen killed at least nine people and injured five as they opened fire at Mar Mina church in the south Cairo district of Helwan, according to state TV

The interior ministry said it arrested the terrorist who attacked the church. The ministry identified the man as Ibrahim Ismail Mostafa, adding that he has carried out multiple attacks against civilians and policemen since 2016.

Friday's attack took place as Egyptian Coptic Christians, who make up 10 percent of the country's 93 million population, make preparations to celebrate Christmas on 7 January.

Police have deployed 230,000 personnel nationwide to secure churches, parks and vital public institutions during Christmas celebrations.