Turkey needs to do more in the fight against the Islamic State of Iraq and the Levant (ISIL) group, US Defence Secretary Ash Carter has said.
Speaking at a Pentagon press conference on Thursday, Carter said the US appreciated Turkey's recent decision to permit US warplanes to fly combat missions out of its air bases but urged its NATO partner to take steps to participate in airstrikes and better control its border.
Carter said top US leaders are in "active discussions" with Turkey about the need to better stem the flow of ISIL fighters crossing its border into Iraq and Syria, adding that fighters and supplies were making their way across the long border.
"It's long overdue because it's a year into the campaign, but they're indicating some considerable effort now, including allowing us to use their air fields. That's important, but it's not enough."
Officials from Turkey's ministry of foreign affairs told Al Jazeera they would soon be responding to the remarks.
Carter said that Turkey had agreed in principle to participate in the coalition bombing campaign against ISIL, but the US also needed Ankara to step up its efforts to control its long border with Iraq and Syria.
The US defence chief defended the military's strategy for defeating ISIL, who overran parts of Syria and Iraq last year before declaring their own caliphate. The strategy calls for training and equipping local forces to fight ISIL fighters, while providing air support for the ground troops.
Turkey says it has been pursuing air campaigns since July targeting the outlawed Kurdistan Workers' Party (PKK) in northern Iraq and ISIL in the north of Syria.
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There have been lingering concerns, however, that Turkey would continue to focus its military forces on Kurdish rebels, and not spend enough effort battling ISIL.
The US has said Turkey has a right to defend itself against the Kurdistan Workers Party, or PKK, which Washington, like Turkey, considers a terrorist group. Turkish officials say the Democratic Union Party, a Syrian Kurdish group fighting ISIL, is not a target of Turkey's operations.
The US-led air campaign has helped blunt the advance of the ISIL group. Kurdish troops in Iraq and northern Syria have made progress in reversing ISIL gains, but Iraqi government troops and US-trained Syrian forces have had difficulties.
"I'm confident that we will succeed in defeating ISIL and that we have the right strategy," Carter said. "But it's complicated not just only in Iraq ... but in Syria as well."
Source: Al Jazeera and agencies