US, Turkey to work closely to deal IS 'lasting defeat': US defence secretary

The United States and Turkey moved to reduce tensions on Friday during a visit to Ankara by the US defence secretary where both sides agreed to ramp up joint efforts to deal Islamic State (IS) militants a "lasting defeat," a Pentagon spokesman said.

In a sign that the US is trying to overcome differences with Turkey after a tense period following the failed 15 July coup attempt, Ashton Carter praised the Turkish military's role in the battle against IS in Syria and Iraq. 

Carter met with President Recep Tayyip Erdogan and Prime Minister Binali Yildirim, as well as Defence Minister Fikri Isik, on a visit to Turkey, which recently launched an offensive in Syria and is a US ally in the battle for Mosul, IS's stronghold in Iraq. 

"Both sides agreed to maintain frequent communication on the full range of mutual interests, including close coordination and continued transparency in the coalition effort to deal ISIL a lasting defeat," Pentagon spokesman Peter Cook said in a statement. 

During talks, Carter reaffirmed his support for the strategic alliance between the US and Turkey and vowed Washington would "continue to stand side-by-side with our NATO ally against shared threats".

Washington is alarmed by tensions between Turkey and Iraq as the long-awaited battle to retake Iraq's second city Mosul from IS militants enters a decisive phase.

Turkey, which fears the Mosul offensive could boost the influence of Kurdish militias hostile to Ankara, says it cannot stay on the sidelines, but Baghdad is firmly against the involvement of Turkish troops.

Iraq's sovereignty 'important'

The US wants Turkey to refrain from military operations in Iraq without the green light from Baghdad, fearing the war of words could jeopordise a fragile pact to keep rival sectarian and ethnic militias out of central Mosul.

Respect for Iraq's sovereignty is an "important principle", Carter told reporters on his plane en route to Turkey. 

A senior US defence official said Washington was urging both sides to "tamp down the rhetoric".

"We have been talking behind the scenes to get the Iraqis and the Turks to come to an understanding on how to move forward on Mosul and on Turkish presence in Iraq," the official said on condition of anonymity.

The visit comes as Turkish warplanes carried out deadly strikes on US-backed militias in northern Syria, including Syrian Kurdish fighters. 

The Turkish army said Thursday the raids killed between 160 and 200 militants from the People's Protection Units (YPG), a group considered a terror group by Ankara but a de facto ally by Washington.

Carter declined to comment on the issue during his flight to Turkey. 

Turkey in August launched Operation Euphrates Shield in northern Syria, sending tanks and troops to back Syrian rebels who have ousted IS from several key areas including Jarabulus and Dabiq.

'Burden of battle'

Rebel fighters captured Dabiq on Sunday in a symbolic setback to the militants, as a Sunni prophecy cites the town as the site of an end-of-times battle between Christian forces and Muslims. 

Carter said the capture of Dabiq was an "important objective" of the campaign.

"The Turks were carrying the burden of the battle here and did spectacularly well," he said.

"We will be working with them to consolidate that border region, long an objective of theirs and ours, and a very important one in the counter-ISIL campaign."

Tensions between NATO allies Ankara and Washington have grown after the failed July coup in Turkey.

Turkish authorities blamed the putsch on a rogue military group led by US-based Muslim preacher Fethullah Gulen - charges he denies - and they have repeatedly demanded his extradition.

Carter on Friday toured the Turkish parliament that was extensively damaged by air strikes on the coup night.

"(He) expressed his condolences to all those who lost their lives defending Turkey's democratically elected government," according to the Pentagon statement.

Carter is due to visit the United Arab Emirates before a meeting of defence ministers from the international anti-IS coalition in Paris on Tuesday. On Wednesday he will join a NATO ministerial gathering in Brussels.