Aug. 23 (UPI) -- In the middle of his five-day Middle East trip Wednesday, U.S. Defense Secretary James Mattis heard concerns from Turkish leaders about the United States' continuing military support for a Kurdish militia in Syria.
Both leaders noted the importance of Syria and Iraq's territorial integrity, but the main topic was U.S. support to the Democratic Union Party's People's Protection Units, also known as YPG.
YPG is affiliated with the Kurdistan Workers' Party (PKK), which itself is listed as a terrorist group by the United States. Turkey's concerns are underscored by the fact Erdogan's regime considers the YPG a national threat
"Turkish relations are as bad as they can get," former senior Turkish diplomat Aydin Selcen, who served in Iraq and Washington, told Voice of America Wednesday. "But the fact Turkey's position on the world map is extremely important, one can look on the map and see without Turkey it will be difficult for the U.S., if not impossible, getting rid of [IS] from Iraq and Syria."
Last June, Mattis sent a letter to Turkish Chief of General Staff Gen. Hulusi Akar to inform Ankara about the weapons the U.S. provides to the YPG.
Another main topic at Wednesday's meeting was potential Turkish military action against the YPG in Syria.
Mattis is nearing the end of his Middle East tour, which includes stops in Iraq, Turkey, Jordan and Ukraine. He will arrive in Kiev Thursday.
Mattis thanked Barzani for being a supportive partner in operations to defeat the Islamic State.
"The secretary congratulated President Barzani on the success in Mosul, and noted the liberation of that city was only possible due to the strong cooperation between Baghdad and Irbil," chief Pentagon spokesperson Dana W. White said Wednesday. "To maintain this cooperation, the secretary encouraged President Barzani to engage in a sustained dialogue with Prime Minister Abadi and keep the focus on maintaining the momentum against ISIS."
During the stop, Mattis asked Barzani to postpone a referendum next month on Kurdish independence.
"Our point right now is to stay focused like a laser beam on the defeat of Daesh and to let nothing distract us," Mattis told reporters.
Kurdish officials, though, said the vote will go ahead as planned.
"We intend to proceed with the referendum on Sept. 25 to allow our people to determine their own future," Masrour Barzani, a top Kurdish security official and the son of Massoud Barzani, said Tuesday night. "This remains the only solution; forced coexistence in Iraq isn't working."
Earlier in Bagdad, Mattis told reporters that the Islamic State "is on the run and they have been shown to be unable to stand up to our team, have not retaken one inch of ground."
Mattis met Iraqi Defense Minister Erfan al-Hayali and noted Iraqi security forces' "determined and heroic efforts" to liberate Iraq from the Islamic State, White said.
Officials said during a meeting with the Iraqi prime minister, "the secretary reaffirmed U.S. dedication to the U.S.-Iraq security partnership, and committed to continued support to improve security for the Iraqi people and deny ISIS terrorists safe haven in Iraq."
Mattis will conclude his Middle East trip after leaving Ukraine Thursday.