Pope Francis on Thursday used his first public remarks since arriving in New York to express solidarity with Muslims after a devastating stampede in Saudi Arabia.

"I want to express the closeness of the church in the face of the tragedy people suffered in Mecca," said the pontiff at the start of his homily during prayers at St Patrick's Cathedral.

The stampede killed at least 717 people and injured hundreds more at the hajj, one of the worst-ever tragedies at the annual Muslim pilgrimage.

"In this moment of prayer, I unite and join in prayer with our almighty God and merciful father," he added.

Pope Francis arrived in New York on the second leg of his six-day US tour, and was greeted by cheering crowds of thousands who lined Fifth Avenue to catch a glimpse of him in his popemobile.

Thursday marked the Muslim feast of Eid al-Adha in America, where more than 1,800 public schools in New York closed for the first time in honor of a Muslim religious holiday.

mar/jm/ec