US forces in Syria and Iraq are "trending downward", he added, without specifying whether the 2,000 troops in Syria included the 400 Marine artillerymen that the Pentagon announced last week would soon leave the country.
Mattis also said that the United States was adjusting its support to the Syrian Democratic Forces, a mix of Kurdish and Arab troops that have led the US-backed fight against ISIS in Syria, suggesting that offensive weapons would no longer be provided to the Kurdish elements of the SDF, a change long sought by America's North Atlantic Treaty Organisation ally Turkey. Manning declined to say how many American troops were in Syria or Iraq at the height of urban combat operations - those in Raqqa or Mosul, for example - that required larger footprints of US combat advisers. "We will be in Syria as long as it takes to make sure that ISIS is not afforded the ability to reestablish safe havens and plan and conduct attacks".
But with Syrian negotiators walking out on the UN-backed Geneva talks this week, the Pentagon offered its heaviest criticism of Russian-led military efforts in recent memory.
However, he promised to be more open in terms of how many troops deployed. Critics say the policy masked the true extent of United States forces fighting IS and prevented the USA military from using support troops, such as mechanics and equipment maintainers in-theater, creating greater reliance on contractors.
Military officials have long said that despite several high-profile ISIS defeats, military operations against the terror group would continue for some time. "Their collective action call into question their commitment to deal a lasting defeat to ISIS and other extremist groups". "Nor do they appear to be serious about the withdrawal of Iranian-backed militias".
Unlike Russia, the United States is not in Syria at the request or approval of the Damascus government.
Yet it's not clear exactly which Syrian partners the remaining American troops will be supporting to create "sustainable" and "ethnically diverse" local security forces.
A U.S. Marine waits to guide an armored vehicle towing an M777A2 howitzer to a firing position in Syria on May 14, 2017. The Arab-dominated RISF that was stood up to stabilize Raqqa is 1,600 members strong and recently graduated 500 new members, coalition spokesman Col. Ryan Dillon said at an August briefing.
Washington has cited Article 51 of a United Nations charter allowing for self-defense of partner forces as legal justification for its military engagement, and that will remain the case going forward. "We're going to go exactly along the lines of what the president announced". "If a major shift occurs, then we'll come back out with a new, official number".