Pope Francis has condemned Israel for using "terrorism" tactics during its aggression on the besieged Gaza Strip.

The pontiff deplored the recent killing by the Israeli military of two Christian women who had taken refuge in a church complex at his weekly address at St. Peter's Square on Sunday.

“I continue to receive very grave and painful news from Gaza,” said the Pope.

“Unarmed civilians are the objects of bombings and shootings. And this happened even inside the Holy Family parish complex, where there are no terrorists, but families, children, people who are sick or disabled, nuns,” he said. 

"Some would say 'It is war. It is terrorism.' Yes, it is war. It is terrorism," he said.

Francis referred to a statement about an incident on Saturday by the Latin Patriarchate of al-Quds, the Catholic authority in the holy city.

The Patriarchate said an Israeli military sniper killed the two women, whom the pope named Nahida Khalil Anton and her daughter Samar, as they walked to a convent of nuns in the compound of the Holy Family Parish.

Seven other people were shot and wounded as they tried to protect others.

The Patriarchate's statement also said that a convent of nuns of the order founded by Mother Teresa was damaged by Israeli tank fire.