The United States is starting to rebuild trust that was lost in its relationship with key NATO ally Turkey after a series of disputes, Secretary of State Rex Tillerson said Monday after meetings with Turkish leaders.

Mr. Tillerson had held several hours of talks the day earlier with President Recep Tayyip Erdogan in Istanbul, hoping to smooth out the two countries’ ties.

He acknowledged that the United States’ relationship with Turkey had “been under some stress for some time”.

“I hope we are beginning to put it on the mend,” he told staff members at the U.S. consulate in Istanbul in a speech to wrap up his two-day visit.

Turkey’s relations with Washington plummeted in the final months of Barack Obama’s administration but Ankara has hoped for an improvement under President Donald Trump.

Ties eroded

But ties are still being eroded by disputes ranging from Syria to the extradition of the alleged organiser of last year’s failed coup to the fate of a U.S. pastor jailed in Turkey since October.

Mr. Tillerson, a former Exxon Mobil chief, said he believed that each time he met Mr. Erdogan “things are getting a little better in terms of the tone between us”.

“I think we’re beginning to rebuild some of that trust that we lost in one another, they lost our trust to a certain extent, we lost theirs.”

But Turkey is furious that Mr. Trump has continued and even expanded Mr. Obama’s policy of supporting the Kurdish People’s Protection Units as the main fighting force on the ground in Syria against Islamic State jihadists.