David Cameron is hoping to send a tough message on Ukraine from the leaders of the West's largest powers as the G7 summit in Germany concludes today.
The Prime Minister last night held talks with US president Barack Obama at which both agreed the need to maintain harsh sanctions against Russia until Moscow shows it has fully implemented last year's Minsk peace agreement.
US President Barack Obama has called for more cooperation between nations to try to stem the flow of foreign would-be jihadists into Syria.
Speaking at the close of the G7 summit in Germany, he said while coalition forces had managed to successfully target many Islamic State strongholds, the continuing influx of fighters from overseas meant a long-term solution was still some way off.
He said he wanted to see "better cooperation, better coordination and better intelligence" - including an improvement in the monitoring of the border between Turkey and Syria.
He said the US was also stepping up efforts to train Iraqi soldiers to fight Islamic State extremists, as well as working with Iraq's government to improve cohesion between the Sunni, Shia and Kurdish communities.
Barack Obama has urged David Cameron to keep meeting the Nato target of spending 2% of GDP on defence.
David Cameron will use the G7 summit in Germany to call for an international effort to clean up governments and businesses around the world.