After arriving from Ukraine, Tillerson met in Istanbul with his Turkish counterpart Mevlut Cavusoglu and was later due to hold talks with President Recep Tayyip Erdogan, officials on both sides said.

Tillerson, the former chief executive of energy giant Exxon Mobil, was also to address the opening ceremony of the World Petroleum Congress in Istanbul.

Turkey's relations with the United States had dropped to lows in the final months of the administration of former president Barack Obama but Ankara had hoped for a new page under Donald Trump.

But it is furious that Trump has continued and even expanded Obama's policy of supporting the Syrian Kurdish People's Protection Units (YPG) as the main fighting force on the ground in Syria against Islamic State (IS) jihadists.

Ankara considers the YPG a terrorist group and the Syrian branch of the Kurdistan Workers' Party (PKK) has waged an insurgency inside Turkey since 1984.

But Washington is openly arming the YPG and the group is heavily involved in the US-backed operation to oust IS jihadists from their stronghold of Raqa.

Turkey has not ruled out a new cross-border operation in Syria against the YPG, which could spark a dangerous escalation with the US.

Meanwhile, Ankara has achieved no more progress on its aim of extraditing the alleged mastermind of the July 15 failed coup, the US-based preacher Fethullah Gulen.

Gulen denies any link with last year's deadly botched putsch.

Frustrated with the Obama administration's apparent lack of interest on the issue, Turkey hoped for a major shift under Trump but this has yet to materialise.

Ankara is also pressing Washington for the release of Turkish Iranian businessman Reza Zarrab and the chief executive of Halkbank Mehmet Hakan Atilla who have been arrested in the United States on charges of helping Iran violate sanctions.

Meanwhile, Washington is also pushing Turkey over the case of Andrew Brunson, a US pastor arrested in the western city of Izmir in October over alleged links to Gulen.

sjw/pg