US Secretary of State John Kerry arrives in Turkey for talks on Israel and Syria
After helping broker a reconciliation between Turkey and Israel, Mr Kerry will urge them to "fully normalise" relations, US officials said.
He will also stress the importance of Turkey keeping its border open to those fleeing the war in Syria, they said.
Turkey is Mr Kerry's first stop of a 10-day trip to Europe and Asia.
He is due to meet Turkish Prime Minister Recep Tayyip Erdogan and Foreign Minister Ahmet Davutoglu.
Officials travelling with Mr Kerry said he would "encourage Turkey to expeditiously implement its agreement with Israel and fully normalise their relationship" ahead of forthcoming talks between the two states.
Mr Kerry will also encourage Turkey to continue admitting civilians fleeing the conflict in Syria, following reports - denied by Turkey - that some Syrians had recently been deported after unrest at a border camp.
More than 1.2 million people have fled to neighbouring countries since the unrest in Syria began two years ago, according to UN figures.
More than 250,000 are in Turkey.
After Turkey, Mr Kerry is due to visit Israel, the West Bank, the UK, South Korea, China and Japan.
Voice of Russia, BBC
The US Secretary of State John Kerry will visit Turkey on Sunday as part of a trip to Europe and Asia to consult allies on issues including Syria's civil war. Washington regards Turkey, which shares a 900-km (560-mile) border with Syria, as a pivotal player in backing the Syrian opposition and planning for an era after Syrian President Bashar al-Assad is gone.
Hardly accidentally, this report coincided with another one published by The Washington Post. The latter tells of the joint efforts taken by The U.S. and Syria's other neighbor, Jordan, to step up training of Syrian opposition forces that may be used to establish a buffer zone along Syria's southern border.
Training begun last year has been expanded and accelerated after rebel gains in the south of Syria. According to Jordanian security officials, the previous timetable to complete training of about 3,000 Free Syrian Army officers by the end of June has been moved up to the end of this month in light of border victories.
In fact, both reports tell the same story. The wider global context emerges from the November 2011 announcement made by the then Secretary of State Hillary Clinton that the U.S. foreign policy is taking a "strategic pivot" and "returning to Asia". This means that from now on the U.S.A. regard China as its main strategic opponent, and therefore, in dealing with areas of "minor" importance, like the Middle East, they may feel restricted in resources to handle the issues themselves.
Another underlying factor is that after burning their fingers (if only fingers) in Iraq and Afghanistan, the U.S.A. can no longer afford direct involvement in volatile areas fraught with numerous financial expenditures and human losses. Hence the desire to rely upon proxies, like in this case, Turkey and Jordan.
And last but definitely not least factor arises from the very fact that, unlike Asia Pacific, the Middle East does not present a direct and immediate danger for the U.S.A. The spread of religious extremism and terrorism mostly affects the neighboring countries. The flow of Afghan drugs is directed to Central Asia, Russia and Europe, therefore the U.S.A. are not inclined to curb the flow at its origins. And now, events in Syria, with all evidence that the so called "Free Syrian Army" is simply a bunch of terrorists of all breeds, are too distant from the U.S. to be a matter of major concern.
This new strategy was clearly demonstrated in regard to Libya, when the U.S.A. let their European allies to do the dirty work, while keeping the low profile themselves.
This is exactly what they are doing now in regard to Syria.
But as one of the bloggers commenting on The Washington Post piece has put it, "We have seen this movie before and this ends badly… By 2001 we are picking dead bodies from rubble in New York, a work of 'freedom fighters'… For the last 11 years U.S. forces are fighting and dying in Afghanistan, combating these 'freedom fighters'. Thousands of madrasas started by Saudi money are still churning out these 'rebels' to fight U.S. troops. And we are supposed to cheer this latest insane initiative in Syria? Are you crazy?"
Indeed, the question is even much more relevant in regard to Syria's immediate neighbors. Whatever their intentions may be, however much they wanted to "free the Syrian people from the oppressive regime", they should take into consideration that their Trans-Atlantic bosses are in a much better position to defend themselves. And the inevitable triumph of most radical and extremist forces in Turkey's and Jordan's immediate neighborhood will primarily backfire against those countries now trying to act as the U.S.A.'s obedient proxies.