U.S. Secretary of Defence Jim Mattis gives a news conference after a NATO defence ministers meeting at the Alliance headquarters in Brussels, Belgium June 29, 2017. REUTERS/Eric Vidal

BRUSSELS (Reuters) - U.S. Defense Secretary Jim Mattis said the United States and its NATO allies likely drew down its big troop presence too quickly from Afghanistan, but he vowed to stick with the war, refusing to put a date on when it might end.

“Looking back on it, it’s pretty much a consensus that we may have pulled our troops out too rapidly, reduced the numbers a little too rapidly,” Mattis told a news conference following a meeting of NATO defense ministers to discuss Afghanistan.

U.S. forces in Afghanistan are below their peak of more than 100,000 troops in 2011, when Washington was under huge domestic political pressure to draw down the costly operation.