(NY Times) -- American military commanders have long argued that arming the Y.P.G., a Kurdish militia fighting alongside Syrian Arab forces against the ISIS, is the fastest way to seize Raqqa, the capital of the militants’ self-proclaimed caliphate.

And Mr. Trump, who made fighting "Islamist militants" a priority during his campaign, again showed the high regard he has for Pentagon generals by endorsing their advice when faced with a policy dilemma.

Turkey has objected vociferously to such a move, raising fears of a backlash that could prompt the Turks to curtail their cooperation with Washington in the struggle against ISIS. 

A high-level delegation of Turkish officials was informed of the decision by Lt. Gen. H. R. McMaster, Mr. Trump’s national security adviser, when they visited the White House on Monday, and the Pentagon announced the move on Tuesday.

The president’s decision comes as his top advisers recommended sending 3,000 to 5,000 more American troops to try to break a stalemate in another hot spot: the 15-year war in Afghanistan.