BEIRUT — Syrian Kurdish-led forces were closing in Saturday on the de-facto capital of the Islamic State in Syria, seizing a cotton factory only a couple of miles north of the city and clashing with militants on a number of fronts, activists and Kurdish media reported.

The Britain-based Syrian Observatory for Human Rights said the Kurdish-led Syrian Democratic Forces, backed by U.S-led coalition airstrikes, advanced in a multi-pronged offensive northeast and northwest of the city.

The offensive brings the SDF 2.5 miles from the northeast of the city, the Observatory said. Fighting was also reported about 3.7 miles north of Raqqa and 8 miles to the northwest, the Observatory said.

The Raqqa Campaign, a Facebook page affiliated with the Kurdish-led forces, said the fighters seized the cotton factory, 2.5 miles north of the city Saturday. Kurdish Hawar news agency said the Kurdish-led fighters also seized the office of a farmer’s union, a local ruling party headquarters and a prison used by the militants. The agency said the fighters seized about 115 miles north of the city in their advance in the last four days.

The Kurdish-led forces said Friday they expect to advance on Raqqa this summer, after their capture of a strategic town and dam about 25 miles west of the city.

Kurdish activist Mustafa Bali said the SDF are moving fast to reach the outskirts of Raqqa, but that the battle for the city is likely to take time. He said in one push, the SDF moved through 5 miles with good air cover, arriving 2.5 miles north of the city.

The activist-run Raqqa Being Slaughtered Silently group said the public markets in Raqqa have been closed, suspecting it is because of the proximity of the clashes. Later, the activist-run group said the militants ordered merchants to evacuate the vegetable market for the next few days. The group didn’t elaborate.

The campaign to recapture Raqqa appeared to be accelerating after a decision by the Trump administration to arm the Kurdish-led forces with heavy weapons, giving a push to their ground partner to move toward the city, held by the militants since 2013.

The weapons have not yet been delivered to the Kurdish-led forces, which include an Arab fighters unit.

Turkey strongly objects to Kurdish-led forces leading the campaign. Turkey considers the main component in the Kurdish-led SDF to be an extension of the domestic insurgents it labels as terrorists, and fears their growing influence in northern Syria.