Pope says migrant crisis "biggest tragedy" since WWII

Pope Francis gives the thumbs up sign as he leaves St. Peter's Square at he end of the weekly general audience at the Vatican, Wednesday, March 22, 2017. (AP Photo/Gregorio Borgia (The Associated Press)

Pope Francis delivers his speech during the weekly general audience he held in St. Peter's Square at the Vatican, Wednesday, March 22, 2017. (AP Photo/Gregorio Borgia) (The Associated Press)

Pope Francis waves to faithful as he arrives in St. Peter's Square at the Vatican for his weekly general audience, Wednesday, March 22, 2017. (AP Photo/Gregorio Borgia) (The Associated Press)

Pope Francis has described Europe's refugee and migrant crisis as the biggest tragedy since World War II.

Francis urged tourists and pilgrims in St. Peter's Square Wednesday during his weekly public audience "not to forget" the problem but instead welcome and help refugees. He also encouraged efforts to integrate them in society.

He said integration should keep in mind "the reciprocal rights and duties of those who welcome and those who are welcomed."

Francis repeatedly urged Europe to do more to help the hundreds of thousands of asylum-seekers and economic migrants who've arrived in recent years.

On Friday, Francis has the opportunity to urge Europe to improve ways to handle the migrant crisis when he addresses leaders of the European Union nations on the eve of a summit in Rome.