New US Secretary of State John Kerry landed in London on Sunday to start his first official trip, a marathon get-acquainted tour of close allies in Europe and the Middle East.
Kerry will meet with British Prime Minister David Cameron and Foreign Secretary William Hague on Monday before visiting Germany, France, Italy, Turkey, Egypt, Saudi Arabia, the United Arab Emirates and Qatar.
He is expected to address issues including Syria, Mali and North Korea.
Kerry's decision to make his first trip to Europe, unlike predecessor Hillary Clinton who chose to tour countries in Asia and the Pacific, sends a strong signal to America's closest European partners, said a senior State Department official.
"The Secretary is very pleased to be able to do this first foreign trip with these key European partners," stressed the official, on board the aircraft carrying Kerry's delegation to London.
"I think it's a real reflection on the degree to which we coordinate our global cooperation with these key partners," he added.
After talks with Cameron, the former presidential candidate will meet with Hague and hold his first news conference of the tour before leaving for Berlin late Monday.
The visit sees Kerry, the son of a diplomat, back on familiar ground. He spent part of his childhood in Berlin, has family in France and is a keen supporter of strong trans-Atlantic ties.
The relationship was boosted ten days ago when President Barack Obama announced that negotiations had started between the US and the European Union to create a massive free trade zone.
"The British have been very supportive of this and other Europeans are very enthusiastic as well," said the official.
But he warned the US had "no illusions about the difficulties and the obstacles" facing the zone's creation.
The burning issue of Syria will crop up throughout Kerry's trip, and a senior US administration official travelling with the secretary on Sunday urged the opposition not to boycott international talks due to be held in Rome on Thursday.
"We are stressing... that they (the opposition) have an opportunity in Rome, to see the countries that have been their greatest supporters and to present to all of us how they see the situation on the ground in security, humanitarian, political and economic terms," said the official.
"This meeting is also an opportunity for them to meet our new secretary of state and to speak directly to him," he added.
Kerry arrives in Paris on Wednesday for talks with French President Francois Hollande and Foreign Minister Laurent Fabius.
The issues of Mali -- where the Americans are providing logistical support to French forces -- Iran, Syria and North Korea will be on the agenda, according to officials of both countries.