Acting US Defence Secretary Patrick Shanahan said on Friday that the United States is committed to defeating Islamic State in the Middle East and beyond, but officials said European allies are sceptical of Washington's pledges.
US President Donald Trump's announcement in December that he was withdrawing all 2,000 US troops from Syria surprised and rattled allies. US officials have crisscrossed the Middle East in recent weeks to reassure them that Washington remains committed to the region.
Trump's Syria decision was opposed by top aides, including Defense Secretary Jim Mattis, who quit, leaving his deputy Shanahan in charge of the Pentagon.
"While the time for US troops on the ground in northeast Syria winds down, the United States remains committed to our coalition's cause, the permanent defeat of ISIS, both in the Middle East and beyond," Shanahan said after a meeting on the sidelines of the Munich Security Conference.
The meeting included about a dozen defense ministers from the coalition to defeat Islamic State. Kurdish-led fighters are battling to capture Islamic State's last major stronghold in Syria, but even without territory, the militant Islamist group is widely seen as a continuing threat.
Shanahan said he envisioned a "bigger and stronger" coalition to fight Islamic State globally. "We will continue to support our local partners' ability to stand up to the remnants of ISIS," he added, using an acronym for Islamic State.
However, European officials said they were given few details during the closed-door meeting in Munich and many questions remain. "We are still trying to understand how the Americans plan to withdraw. I don't think there is any clarity still," one European official, speaking on the condition of anonymity said.
Another official said Shanahan did not provide allies with a timeline of the American withdrawal from Syria and allies expressed scepticism during the meeting.
A senior US defense official, speaking on the condition of anonymity, said no commitments were made during the meeting and there was little discussion about timelines.
"These meetings don't tend to have specific deliverables or decisions, it tends to be more focused on taking stock of where we are," the US official said.
Trump has said he expects a formal announcement as early as this week that the coalition fighting Islamic State has reclaimed all the territory held by the group.