G7 leaders meeting in Italy on Friday and Saturday will attempt to put on a united front against terrorism given their differences over climate change and global trade.

The summit in Sicily’s ancient hilltop resort of Taormina kicks off four days after children were among 22 people killed in a concert bomb attack in Manchester.

British Prime Minister Theresa May will lead a discussion on terrorism in one of Friday’s working sessions and is expected to issue a call for G7 countries to put more pressure on internet companies to remove extremist content.

With May and Donald Trump among four new faces in the club of the world’s major democracies, the gathering in Italy is being billed as a key test of how serious the new US administration is about implementing its radical policy agenda, particularly on climate change.

Senior officials are also preparing to work through the night of Friday-Saturday in a bid to bridge what appear to be irreconcilable differences over Trump’s declared intention of ditching the US commitment to the landmark Paris according on curbing carbon emissions.

Leaders of the world’s rich nations are braced for contentious talks with Trump after he lambasted NATO allies for not spending more on defense and accused Germany of “very bad” trade policies.

Trump’s confrontational remarks in Brussels, on the eve of the two-day summit, cast a pall over a meeting at which America’s partners had hoped to coax him into softening his stances on trade and climate change.

Officials acknowledge the summit, one of the shortest in the body’s history, is effectively about damage limitation against a backdrop of fears among US partners that the Trump presidency, with its “America First” rhetoric, could undermine the architecture of the post-World War II world.

Summit host Paolo Gentiloni, a caretaker Italian prime minister also making his G7 debut, acknowledged as much on the eve of the meeting.

“It won’t be an easy discussion,” he said. “The Italian presidency will try to ensure it is a useful one, capable of bringing the different positions closer together.”

The other new face is France’s youthful president, Emmanuel Macron, who has vowed to defend the Paris climate change deal agreed in 2015.

“On the climate question it might be important to have the whole night to reach a consensus,” a German government source said.

“Europe has a common position on that, but we have to get the whole G7 together.”

The effort to keep Trump onboard will focus on convincing his team that developing renewable energy forms and technology to facilitate cleaner fossil fuels can be drivers of the job-creating growth that he says is his priority.

“If we do it right climate protection and growth go hand in hand — and then it is not really important if it is a man-made problem or not,” said the German source.

Trump’s economic advisor Gary Cohn said Friday US compliance with its Paris commitments would be “crippling” to economic growth, but added the president was “interested to hear what the G7 leaders have to say about climate”.

“We will have a very robust discussion on trade and we will be talking about what free and open means.”

He also predicted “fairly robust” talks on whether Trump should honor a US commitment to cut greenhouse gas emissions under the 2015 Paris Agreement.

European leaders have signaled that they will push Trump hard on the Paris emissions deal, which has comprehensive support across the continent.

On the major security questions due to be addressed — Syria, Libya and North Korea — there is broad agreement among the G7 countries, although the importance of each varies.

Italy chose to stage the summit in Sicily to draw attention to Africa, which is 140 miles (225 km) from the island at its closest point across the Mediterranean.

More than half a million migrants, most from sub-Saharan Africa, have reached Italy by boat since 2014, taking advantage of the chaos in Libya to launch their perilous crossings.

Italy is eager for wealthy nations to do much more to help develop Africa’s economy and make it more appealing for youngsters to stay in their home countries.

The leaders of Tunisia, Ethiopia, Niger, Nigeria and Kenya will join the discussions on Saturday to say what should be done to encourage investment and innovation on their continent.

One country that won’t be present is Russia. It was expelled from the group in 2014 following its annexation of Crimea from Ukraine.