BEIRUT: A Syrian Kurdish militia Wednesday recaptured a town that had been stormed by ISIS fighters earlier this week north of the jihadist group's base of operations in Raqqa city, the Syrian Observatory for Human Rights reported.

ISIS fighters had stormed the town of Ain Issa Monday, part of a wider attack by the jihadi group on areas held by the Kurdish YPG militia. Ain Issa is 50 km (30 miles) north of Raqqa city.

The latest advance by the YPG comes amid to-and-fro battles with ISIS fighters across northern Syria, who have also been clashing with the Syrian military around Hassakeh city further east.

A drone strike as part of a U.S.-led air campaign against ISIS killed a senior figure from the group in Raqqa city overnight, the Observatory said earlier Wednesday. The strike killed an Uzbek leader of the group involved in security as he sat in a car outside a downtown hotel.

ISIS has attracted foreign fighters from across the world to fight in its self-declared caliphate across parts of Syria and Iraq. It has named Raqqa its de-facto capital.

The United States says it has intensified an aerial campaign against ISIS in Syria with a wave of strikes in and around Raqqa city.

U.S. Defense Secretary Ash Carter said Monday heavy bombardment during the weekend that also included destroying bridges over waterways in the city, which is bordered to the south by the Euphrates river, was aimed at further eroding the militants' capabilities.