The long delayed battle to capture Raqqa is imminent after the United States formally announced that it has begun to arm the Syrian Kurdish People’s Protection Units (YPG), the coalition’s premier ally in the war against the Islamic State in Syria.

An official from the Syrian Defense Forces (SDF), the umbrella group that brings together the YPG and its Arab allies from the Syrian Arab Coalition (SAC), told Al-Monitor that the offensive will begin in the coming weeks. “It's unlikely, but … maybe even tomorrow [June 2],” the SDF official said.

The noose around Raqqa, the capital of the IS “caliphate,” has been tightening as thousands of YPG and Arab fighters advised by US special operations forces have encircled it from the north, the west and the east. They have now pushed to within about 2 miles of the mainly Arab city where IS will likely put up fierce resistance, as it has in Mosul in neighboring Iraq.

One of the biggest decisions is how much of a physical US presence will be necessary to ensure that the battle is won and swiftly. Nicholas A. Heras, a Bacevich fellow at the Center for a New American Security, told Al-Monitor, “The coalition is asking a militia force with airpower to seize a city that is likely to be heavily contested by IS. That reality will demand a more hands-on US and coalition partner military presence with the SDF/SAC, and will put the coalition advisers on or near the frontlines.”