Pope Francis greeted the crowds enthusiastically during Sunday's Regina Caeli prayer.
In St. Peter's Square, thousands of people were waiting for him under the Roman sun.
In his address, the pope made a strong appeal for peace in the Middle East. He said the news of Iran's response in Israel on April 13 caused him great concern.
"I follow with prayer and concern and also pain the news in the last hours about the worsening situation in Israel due to Iran's intervention," Pope Francis said. "I make a heartfelt plea to stop all actions that could fuel a spiral of violence and that could drag the Middle East into an even greater conflict."
The pope insisted that Israelis and Palestinians must live in “two states, side by side” in peace and security. He also called for a cease-fire in Gaza and for the release of the hostages kidnapped by Hamas.
Pope Francis emphasized his message and received a standing ovation from pilgrims in the square.
"No more war; no more attacks; no more violence," he said. "Yes to dialogue and yes to peace."
The pope took this opportunity to recall that the first World Children's Day will be celebrated in Rome on May 25 and 26.