US Secretary of State John Kerry urged Turkish leaders on Sunday to speedily restore full diplomatic relations with Israel, two allies the US sees as anchors of stability in a Middle East wracked by Syria's civil conflict, regional political upheavals and the potential threat posed by Iran's nuclear program.

Turkey, however, demanded that Israel end all "embargoes" against the Palestinians first.

US Secretary of State John Kerry speaks during a news conference with his Turkish counterpart Ahmet Davutoglu, unseen, in Istanbul, Turkey, on Sunday. [Photo/Agencies]

In Istanbul on the first leg of a 10-day overseas trip, Kerry met with Turkish Foreign Minister Ahmet Davutoglu with the aim of firming up the rapprochement between Turkey and Israel that President Barack Obama kick-started during a visit to the Jewish state last month.

Kerry met later on Sunday with Turkish Prime Minister Recep Tayyip Erdogan before traveling on to Israel.

"We would like to see this relationship that is important to stability in the Middle East and critical to the peace process ... get back on track in its full measure," Kerry said. He said that meant promises of "compensation be fulfilled, ambassadors be returned and full relations be embraced".

The two nations were once close partners, but the relationship plummeted in 2010 after an Israeli raid on a flotilla bound for the Gaza Strip. Eight Turks and a Turkish-American died.

Before leaving Israel two weeks ago, Obama arranged a telephone conversation between Israeli Prime Minister Benjamin Netanyahu and Erdogan. Netanyahu apologized for the incident, and compensation talks are expected to begin this week.

But Davutoglu suggested that full normalization of ties would probably take some time.

"There is an offense that has been committed and there needs to be accountability," Davutoglu said. He signaled that Turkey would pursue a "careful" advance toward a complete restoration of relations, with compensation and an end to Israeli trade restrictions on the Gaza Strip.

"All of the embargoes should be eliminated once and for all," he said.

Fixing the Turkish-Israeli relationship has been a long-sought goal of the Obama administration, and the United States desperately wants significant progress by the time Erdogan visits the White House in mid-May.

The Turks have reveled somewhat in what they view as a diplomatic victory, with billboards in Ankara celebrating Netanyahu's apology and praising Erdogan for bringing pride to his country.

Perhaps seeking to buffer his leverage further, Erdogan signaled shortly after the call that he was in no hurry to finalize the deal and pledged to visit the Hamas-controlled Palestinian territory soon, the Associated Press reported.

From a US strategic sense, cooperation between its allies has only become more important as Syria's two-year conflict has grown ever deadlier. More than 70,000 people have died, according to the United Nations, but the US fears it could get even worse - by spilling into neighboring countries or through chemical weapons being used. Both potential scenarios have prompted intense contingency planning among Washington and its regional partners, Israel and Turkey included.

After talks in Turkey, Kerry headed later on Sunday to Israel and Ramallah in the West Bank, where he was scheduled to meet with Palestinian President Mahmoud Abbas. He was also scheduled to meet with Netanyahu on Monday.

US officials have said the visit will give him a chance to probe possibilities for restarting the moribund peace process in the wake of Obama's trip last month.

AP-AFP-Reuters