JAKARTA, Indonesia -- Turkey's air and ground offensive against Kurds in northwestern Syria has distracted from international efforts to finish off the Islamic State of Iraq and Syria (ISIS) and has disrupted humanitarian relief work, U.S. Defense Secretary Jim Mattis said Tuesday.

Mattis raised the matter in an exchange with reporters after unrelated meetings in the Indonesia capital with senior government officials. He made clear that while the U.S. sympathizes with Turkey's concerns about border security, Washington wants the Turks to minimize their military action inside Syria.

The Turkish offensive began Saturday, targeting Kurds in an enclave called Afrin. Turkey says it intends to create a 20-mile deep "secure zone" in Afrin. Mattis had said Monday that the Turks gave Washington advance notice that their forces were going to strike Kurds in Afrin.

On Tuesday, Mattis's level of concern seemed to have grown as the fighting continued.

"The violence in Afrin disrupts what was a relatively stable area of Syria," he said. "It distracts from the international efforts to ensure the defeat of ISIS, and this could be exploited by ISIS and al Qaeda, obviously, that we're not staying focused on them right now."

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He said work on stabilizing the Afrin area of Syria had reached the point where much-needed humanitarian assistance was flowing and refugees were returning.

"This clearly disrupts that effort," Mattis said. "The Turkish incursion disrupts that effort."

"So we urge Turkey to exercise restraint in the military actions and the rhetoric and ensure that its operations are limited in scope and duration," he added.

The Pentagon chief said the U.S. and its Kurdish partners, known as the YPG, were "on the cusp" of fully defeating ISIS in Syria.

Mattis raised the matter with reporters after a full day of meetings with Indonesian government officials about ways of extending U.S.-Indonesian military ties. His visit to Jakarta is an early demonstration of a key tenet of the new U.S. defense strategy that Mattis announced last Friday, namely that Washington will work to nurture existing alliances and partnerships and build new ones.

The U.S. has had a long but sometimes complicated relationship with the Indonesian military. After reported humanitarian abuses in the 1990s by a special operations group known as Kopassus, the U.S. cut off military cooperation. In 2010, the U.S. partially restored military-to-military ties, and Mattis said the Indonesians are eager to further expand cooperation with the U.S. military.

Asked whether he believes the Indonesian special forces units have reformed sufficiently to merit resuming U.S. military cooperation, Mattis said, "Yes," adding that the Pentagon will follow established procedures for further easing its restrictions.

Indonesia's special forces were accused of major abuses through the 1990s in the provinces of Papua and Aceh and in East Timor, a former province that has gained independence. The U.S. cut ties with the special forces under a 1997 law that banned U.S. training for foreign military units accused of human rights violations. The ban can be lifted if there have been substantial measures to bring culprits to justice.

In remarks to reporters after his meeting with Mattis, the Indonesian defense minister, Ryamizard Ryacudu, said Mattis promised he would work to further remove the restrictions. The Indonesia minister expressed optimism that Mattis would prevail, even if President Donald Trump were to resist.

"Donald Trump is tough, but Mattis is most heard in the Cabinet there because he is the wisest person, he is a tough soldier but he is wise," Ryamizard said.