(Pope Francis gestures during a meeting with Asian youths at the Solmoe Shrine in Dangjin August 15, 2014. The pope began his five-day trip to South Korea on Thursday. The main purpose of the trip is to preside at the gathering of Asian Catholic youth and beatify 124 people killed for their faith in the 18th century. REUTERS/Ahn Young-joon/Pool )

(Pope Francis gestures during a meeting with Asian youths at the Solmoe Shrine in Dangjin August 15, 2014. REUTERS/Ahn Young-joon/Pool )

Pope Francis said on Monday the international community would be justified in stopping Islamist militants in Iraq, but that it should not be up to a single nation to decide how to intervene in the conflict.

The leader of the world’s 1.2 billion Roman Catholics made his comments in an hour-long conversation with reporters aboard a plane returning from a trip to South Korea that ranged from international diplomacy to his health and future travel plans.

During the encounter that has become a tradition at the end of his foreign journeys, Francis, 77, also said he planned to visit the United States next year and that he was ready to go to China “tomorrow” if the communist government allowed him.

He said he realised he had to slow down and be more “prudent” with his health and that he had learned how to handle the super-star status he has gained since coming to office last year by thinking of his errors and his own imminent mortality.