U.S. Defense Secretary Jim Mattis made clear Thursday that America is committed to protecting Turkey after angering its NATO ally with a deal to arm anti-Islamic State fighters in Syria that Turkey considers terrorists.

 

Mattis stressed the enduring nature of the U.S.-Turkey relationship in a meeting with Prime Minister Binali Yildirim, the first face-to-face contact between officials from the two countries since the U.S. announcement about military support for the Syrian Kurds.

 

The defense secretary, speaking to reporters aboard a U.S. military airplane after the meeting in London, characterized the discussions as "honest, transparent and helpful." Their half-hour conversation took place before an international conference on Somalia, and Mattis said he had no doubt the U.S. and Turkey would "work this out with due consideration and significant attention paid to Turkey's security, to NATO's security and the continuing campaign against ISIS."

 

The U.S. is convinced that the Kurdish fighters, known as the YPG, are the most effective local force in trying to oust IS militants from their stronghold in Raqqa, Syria. Turkey wants the arms agreement reversed. Its leaders have railed against any strategy that, in their view, would involve the U.S. using one terrorist group to fight another.

 

Washington is trying to provide Turkey assurances. A senior American official said the U.S. will step up joint intelligence-sharing with the Turks to help them better target terrorists. The move, first reported by The Wall Street Journal, is one of the things Washington is offering to ease Turkish concerns that the weapons will end up in enemy hands. The official, who wasn't authorized to discuss the issue publicly and spoke on condition of anonymity, said the U.S. has yet to provide the weapons.

 

Mattis acknowledged Turkey's concerns that weapons could end up in the hands of the Kurdish militants in Turkey, known as the PKK. Like Turkey, the U.S. considers that group a terrorist organization.

 

"We support Turkey in its fight against PKK," he said. "We do not ever give weapons to the PKK. We never have and never will."

 

Before his meeting with Mattis, Yildirim had warned that "there is still an opportunity for the United States to take Turkey's sensitivities into consideration. Otherwise, the outcome won't only affect Turkey. A negative outcome will also emerge for the United States."

 

Mattis has played down the friction between the allies, saying that while "it's not always tidy," they will resolve any differences.

 

Turkey's president, Recep Tayyip Erdogan, is to visit President Donald Trump in Washington next Tuesday. Erdogan has demanded that Washington undo the arms decision, and said he would take up the issue with Trump.

 

The Trump administration has not specified the kinds of arms to be provided. U.S. officials have indicated that 120 mm mortars, machine guns, ammunition and light armored vehicles were possibilities. The officials, who spoke on condition of anonymity because they weren't authorized to publicly discuss the matter, said artillery or surface-to-air missiles would not be provided.

 

A spokesman for the U.S.-led coalition against IS, Col. John Dorrian, said Wednesday that the weapons would be delivered to the Kurds soon. He and other officials have said the U.S. will closely monitor the weapons' distribution and insure that they are used only against IS.

 

The Syrian Kurds have been encircling Raqqa, preparing for the launch of what the U.S. military predicts will be a long and difficult battle to retake the city.