The leaders of the world's twenty largest economies gathered for the traditional 'family photo' at the G20 summit in Hamburg, Germany on Friday (7 July).

The world's eyes are on the summit as it forms the backdrop for the first meeting between US President Donald Trump and Russian President Vladimir Putin.

The two leaders were pictured shaking hands at the start of the summit and will hold a meeting later today in which they are expected to discuss foreign policy in the Middle East as well as moves to tackle terrorism. The US president has remained elusive about whether he will raise Russia's intervention in the presidential election with Putin.

On the eve of the summit, Trump called on Putin to end the Ukraine conflict and Moscow's support for "hostile regimes", urging him to join the "community of responsible nations" in their fight against common enemies.

Climate change and trade are set to dominate the agenda of this year's summit, which German Chancellor Angela Merkel strategically decided to hold in Hamburg, the country's tech powerhouse.

"We are all aware of the great global challenges," Merkel said at the start of the summit. "We know that time is short and therefore solutions very often can only be found if we are ready to compromise and work together without bending over backwards too much because, of course, we can express different views on some issues."

Canadian Prime Minister Justin Trudeau is urging other world leaders to convince Trump to change his stance on climate change. "We'll tell him it's important to take a lead role in tackling climate change and creating good jobs," he told German newspaper Bild.

Protests broke out across Hamburg in the run-up to the summit. 76 police officers were injured after clashing with demonstrators and US First Lady Melania Trump was unable to leave her hotel, trapped as an angry crowd gathered outside.

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The 2017 G20 summit is chaired by German Chancellor Angela Merkel REUTERS/Wolfgang Rattay