US secretary of defense details moves in Syria, discusses NATO meetings.

Not all U.S. troops will leave Syria, the US Defense Secretary Dr. Mark T. Esper said at the conclusion of NATO meetings in Brussels.

US Defense Secretary Dr. Mark T. Esper (Picture source: NATO)

Esper said the halt in operations along the Turkey-Syria border is welcome. He called on Turkey to abide by its commitment to protect innocent civilians and minorities and to ensure Islamic State prisoners do not escape.

''We are withdrawing from Northeastern Syria at the direction of the president,'' he said. ''That deliberate withdrawal began with the less than 50 troops in the immediate zone of attack, and we are now in the phase two withdrawal.''

Esper said the United States will maintain a presence at the Al-Tanf garrison. ''We are also considering how we might reposition forces in the area in order to ensure the oil fields,'' he said. ''We are reinforcing that position, and it will include some mechanized forces, and I am not going to get into details.''

The U.S. efforts in Syria aim to ensure ISIS does not reconstitute. ''The United States will maintain a reduced presence in Syria to deny ISIS access to oil revenue as we reposition for the next phase of the Defeat-ISIS campaign,'' Esper said.

The NATO defense ministers meetings set the stage for the NATO leaders meeting in London in December. The 29 defense ministers discussed a number of alliance efforts during their two-day meeting.

Afghanistan was a primary topic, and the alliance is fully committed to the Resolute Support Mission. The United States has 8,475 service members in Afghanistan out of a total contribution of 17,178 from NATO allies and partners.

''Along with our objective of ensuring terrorists are never again able to attack our homelands from Afghanistan, we all agree that the best way to achieve this outcome is through an enduring political settlement,'' Esper said.

The conditions in Afghanistan are changing, and the United States and its allies and partners will tailor forces in the country to match the situation. The government held successful elections last month, and more and more Afghan security personnel have received training.

''Our goal is to have a sustainable force that meets the requirements of the mission,'' he said. ''We will continue to consult with our allies, along with the Afghan government, to refine the way ahead in Afghanistan.''

The NATO ministers discussed the threat posed by Russia and the hybrid warfare Russian leaders have launched against NATO nations. The ministers also discussed the threat to NATO from China.

Esper also stressed the need for more equitable burden-sharing among allies, and he called on them to meet the goal of dedicating 2% of gross domestic product for defense, which they agreed to at the Wales Summit in 2014.

The ministers also discussed the NATO Readiness Initiative, and Esper said all forces for this program should be identified in time for the leaders meeting in December.