U.S. President Barack Obama has arrived in Northern Ireland at the start of a two-day summit for the Group of Eight leading industrialized nations (G8).
Obama spoke to university students in Belfast shortly after his arrival, urging them to strongly support the peace process there.
The conflict in Syrian is expected to be high on the summit agenda.
The White House says Syria will also likely be the focus of talks between Obama and Russian President Vladimir Putin on the sidelines of the summit.
The United States last week announced it would arm Syria's rebels after claiming the regime of Bashar al-Assad had used chemical weapons.
On June 17, Putin defended his administration's arming of Assad, claiming Russia was not breaking international law.
"[I]f we speak calmly and professionally, then I want to draw your attention to the fact that Russia supplies arms to the legitimate government of Syria in full compliance with international law," he said. "We are not breaching any laws, let me emphasize that: nothing. We call on all our partners to act in the same fashion."
Putin questioned why the West would want to arm Syrian rebels who he said ate human organs.
"I believe one does not really need to support the people who not only kill their enemies, but open up their bodies, eat their intestines in front of the public gaze and cameras," he said. "Are these the people you want to support? Are they the ones you want to supply with weapons?"
He was speaking after talks in London with British Prime Minister David Cameron, who maintained that it was vital that Assad was removed from power.
"Almost 100,000 people have lost their lives in this war," he said. "The daily crimes there plumb new depths in the history of the region. Every month that passes leaves more dead, and Syria more dangerous to the region and to all of us. We must work together to do everything we can to bring this dreadful conflict to an end."
Cameron also said Russia and Britain can overcome their differences on Syria.
Besides Syria, Cameron wants the G8 summit to produce new agreements on tax, trade, and financial transparency.
The G8 summit is also likely to consider the impact of the election of moderate cleric Hassan Rohani as Iran's new president.
Cameron is being joined by Obama, Putin, and the leaders of France, Germany, Italy, Canada, and Japan.
With reporting by AFP, AP, and Reuters