US President Donald Trump is meeting leaders of the world’s other major economies at his first G7 summit, held in a cliff-top hotel in Sicily.
They are discussing foreign policy and security, with the Manchester bombing casting a shadow over the meeting.
A tough debate is expected on issues like trade and climate change, already raised in Brussels at talks between Mr Trump and EU leaders on Thursday.
European Council chief Donald Tusk predicted a difficult summit.
“No doubt, this will be the most challenging G7 summit in years,” he said as the summit got under way in Taormina, a town on the Italian island which overlooks the Mediterranean.
The G7 consists of Canada, France, Germany, Italy, Japan, the UK and the US, while the EU also has representatives present.
It is also the first G7 summit for French President Emmanuel Macron, UK Prime Minister Theresa May and Italian Prime Minister Paolo Gentiloni
Fresh from his public dressing-down of Nato leaders for not spending enough on defence, Mr Trump is expected to be just as ready to take on his G7 counterparts, the BBC’s James Landale in Sicily reports.
There will be agreement on the need to do more to tackle violent extremism, and there will be serious discussion with Japan’s prime minister about the threat from North Korea, our correspondent says.
What did Trump say about the Germans?
Other G7 leaders are concerned the US president might promote a protectionist agenda.
German weekly Der Spiegel quoted Mr Trump as saying in a meeting with European Commission President Jean-Claude Juncker on Thursday that Germans were “very bad” on its car sales to the US, and vowed to “stop this”.
Mr Juncker later described the media reports as exaggerated, and said it was “not true that the president took an aggressive approach” towards Germany.
During his election campaign Mr Trump threatened customs duties in retaliation for Germany’s trade surplus with the US, saying it owed “vast sums of money” to the US and Nato.
Speaking ahead of the summit, White House economic adviser Gary Cohn sought to clarify the president’s position.
“What the president means by free and open is, we will treat you the way you treat us, meaning if you don’t have barriers to trade or you don’t have tariffs, we won’t have tariffs,” he said, quoted by Reuters.
Is there common ground on climate change?
Mr Trump will be urged not to abandon the 2015 Paris agreement to tackle global warming; and he will resist moves to limit protectionism in global trade.
During his election campaign, Mr Trump promised to leave the climate accord but he has since postponed his decision.
Mr Cohn said Mr Trump would decide when he returned home from the summit.
What about Manchester?
The summit comes just days after Monday’s deadly bombing in Manchester in which 22 people, including children, were killed.
Mrs May is expected to urge world leaders to do more to combat online extremism, saying the fight against so-called Islamic State (IS) is “moving from the battlefield to the internet”
The UK government has urged technology companies to do more to remove harmful content including extremist propaganda and bomb-making guides from their networks.
Mrs May is expected to lead Friday’s discussion on security and counter-terrorism but will cut short her visit and miss the programme on Saturday.
What did Trump and Abe decide?
The US president and Japanese Prime Minister Shinzo Abe discussed the nuclear and missile threat from North Korea.
They agreed to “enhance sanctions on North Korea, including by identifying and sanctioning entities that support North Korea’s ballistic missile and nuclear programs”, the White House said.
What else has happened in Trump’s first foreign tour?
Addressing a Nato summit in Brussels on Thursday, Mr Trump warned that all members of the alliance should contribute more financially on defence.
Nato states’ contributions are voluntary and a target of spending 2% of GDP on defence is only a guideline, but the US is concerned that members are not paying enough.
The bloc later agreed that member-states would report back annually on defence spending to Nato.
It also said it would take a bigger role in the campaign against IS militants, but France and Germany have insisted the move is mostly symbolic.
The G7 summit brings Mr Trump’s first foreign tour as US president to a close. Earlier in the week, he said he was “more determined than ever” to pursue peace in the world after meeting Pope Francis at the Vatican.
Before that, he vowed to help Israelis and Palestinians achieve peace, as he ended the Middle East leg of his tour.
He began his foreign trip with a two-day stop in Saudi Arabia over the weekend, urging Muslim countries to take the lead in combating radicalisation.