VATICAN CITY — Pope Francis on Monday again pressed the international community to do something about the killing of Christians in several parts of the world and not "look the other way."

He has been increasingly vocal about the fate of Christians being targeted by Islamic extremists in parts of the Middle East, Africa and Asia.

Addressing pilgrims and tourists in St. Peter's Square, Francis praised those who were "sensitizing public opinion about the persecution of Christians in the world."

While not suggesting any particular course of action, he urged "concrete participation and tangible help in defense and protection of our brothers and our sisters, who are persecuted, exiled, slain, beheaded, solely for being Christian."

The pope was building on his Good Friday denunciation of what he then called "complicit silence" about the targeting of Christians.

"They are our martyrs of today, and they are many. We can say that they are more numerous than in the first centuries," Francis said.

"I hope that the international community doesn't stand mute and inert before such unacceptable crimes, which constitute a worrisome erosion of the most elementary human rights. I truly hope that the international community doesn't look the other way," the pontiff said, speaking from a window of the Apostolic Palace.

The advance of Islamic State group fighters has forced members of ancient Christian communities to flee their homes in Iraq.

Francis has been keen on ensuring these Christians feel the Vatican's concern.

On Easter, a Vatican cardinal, Fernando Filoni, celebrated Mass in a Kurdish area of Iraq, and a day earlier, led prayers in a tent in a refugee camp in Irbil.