Pope Francis has warned world leaders against forming "dangerous" and distorting alliances that could harm the poor and migrants, including between the US and Russia.

The 79-year-old Argentine made the comments to Italian newspaper la Repubblica on Saturday (8 July) as world leaders gathered for the G20 conference in Hamburg.

"The G20 worries me, it hits migrants in countries in half of the world and it hits them even more as time goes by," he was quoted as saying, according to Reuters.

Pope Francis, the first non-European pope in 1,300 years, went on to say he was afraid of "very dangerous alliances among [foreign] powers that have a distorted vision of the world: America and Russia, China and North Korea, [Vladimir] Putin and [Bashar al-]Assad in the war in Syria."

He said the greatest danger concerned immigration, with "the poor, the weak, the excluded and the marginalised" juxtaposed with "those who... fear the invasion of migrants. This is why the G20 worries me: It mainly hits immigrants."

The G20 saw world leaders discuss Europe's migration crisis which has seen thousands die while trying to illegally cross the Mediterranean Sea from north Africa.

Pope Francis, who warned Europe to adopt a federal structure as soon as possible or "it won't count for anything in the world", had earlier in the year urged the continent not to see migrants as criminals.

Italy, which has become the main destination for migrants flowing from north Africa, has urged other European leaders to help ease the pressure, saying it can no longer cope with the numbers being brought to its shores.

In the first six months of this year 85,183 people have been rescued in the Mediterranean – a 19% increase on the same period in 2016.

The G20 also saw US President Donald Trump and Russia's Vladimir Putin hold their first official meeting.

"If we can build a relationship along the lines of our conversation yesterday, then there is every reason to believe we can restore, at least to a certain degree, the level of co-operation we need," Putin later said of his meeting with Trump.

Donald Trump Pope Francis
Donald Trump meets Pope Francis at The Vatican EVAN VUCCI/AFP/Getty Images