Tony Gentile / Reuters Pope Francis, seen outside the Vatican, has warned that the G20 leaders have formed "very dangerous alliances" and have a "distorted vision of the world."

Pope Francis has expressed concern about a “very dangerous” alliance between the U.S. and Russia, saying its leaders are among those that have a “distorted vision of the world” when it comes to immigration.

The pope, in an interview with an Italian newspaper on Thursday, lumped the two countries’ relationship in with those of China and North Korea and Russia and Syria as some of the top world leaders met at the G-20 summit in Germany.

“I worry about very dangerous alliances between powers which have a distorted vision of the world: America and Russia, China and North Korea, (Russian President Vladimir) Putin and (Syria’s Bashar al-) Assad over the war in Syria,” the pope told La Repubblica newspaper.

Axel Schmidt / Reuters Leaders attend the G-20 summit dinner in Hamburg, Germany, on Friday. The pope criticized the U.S. and Russia, among other countries, for having a “distorted vision of the world.”

“The danger concerns immigration,” the pope said, according to a translation by AFP. “Our main and unfortunately growing problem in the world today is that of the poor, the weak, the excluded, which includes migrants.”

The warning came one day before President Donald Trump held his first face-to-face meeting with Russian President Vladimir Putin. Though the meeting was scheduled to last only 30 minutes, it went on for hours with both men singing praises of one another.

The pope has previously expressed concerns over Russia’s annexation of Ukraine’s Crimea region. He has also criticized Trump over his stance on immigration, at one point saying Trump “is not Christian” because of his determination to build border walls.

POOL New / Reuters The pope has been critical of President Trump's handling of immigration, at one time saying he is "not Christian."

“Migrants are our brothers and sisters in search of a better life, far away from poverty, hunger, and war,” the pope’s Twitter account tweeted on Saturday.

In his interview, he went on to ask that the leaders of Europe, which he described as the “richest continent in the whole world,” not try to succumb to an illusion that they can seal their borders.

The G-20, a meeting of 19 countries’ leaders plus the European Union, traditionally aims at addressing global financial and economic issues. The countries involved make up nearly two-thirds of the world’s population and three-quarters of global trade. Other issues this year included climate policy and women’s economic empowerment.