Pope Francis on Friday denounced the deaths of thousands of children in a "whirlwind of violence" in the Gaza Strip, Ukraine, and Yemen.

Francis has issued multiple appeals for peace and on Wednesday called for an "immediate humanitarian cease-fire" between Israel and Hamas militants.

"Do you know how many children have died in Gaza in this last war? More than 3,000. It is incredible, but it is the reality," Francis said.

"And in Ukraine there are more than 500, and in Yemen, in years of war, thousands. Their memory leads us to be ourselves lights for the world, to touch the hearts of many people, especially those who can stop the whirlwind of violence."

His remarks were part of a written speech that was not read out, but handed over to members of the Azione Cattolica, the Vatican said in a statement.

U.N. children agency UNICEF said on Wednesday that more than 5,000 children have reportedly been killed in the Gaza Strip and thousands more wounded.

Unrelenting Israeli bombardment has laid much of Gaza to waste over the past two months, with nearly 19,000 people confirmed dead, according to Palestinian health officials.

Israeli raids are a response to an Oct. 7 Hamas attack on southern Israel, in which 1,200 Israelis were killed and more than 200 taken hostage.