London, Washington- The US-led coalition fighting ISIS warned on Thursday Syria’s opposition from fighting regime forces in the desert, and said they need to focus on combating ISIS in eastern Syria.

Coalition spokesman US Army Col. Ryan Dillon said: “The coalition supports only those forces committed to fighting ISIS.”

Meanwhile, CNN channel quoted sources as saying that one US-backed group which calls itself “the Shohada Al Quartyan” and is trained by Western experts at al-Tanf military camp, has balked at the restriction, choosing to leave the base and carry out independent operations against Syrian regime troops.

“The coalition is making it clear to Shohada Al Quartyan leadership that if they choose to pursue other objectives, the coalition will no longer support their operations,” Dillon said, adding that the coalition has cut ties with the group.

Separately, US Special Presidential Envoy for the Global Coalition to Counter ISIS, Brett McGurk said in a letter sent by the US Department of State to Asharq Al-Awsat newspaper that the “accelerated military campaign to liberate Raqqa means that we need to double our efforts for determining, coordinating and financing plans to achieve stability.”

McGurk said the UN needs additional $140 million for humanitarian aid to answer those needs in Raqqa, the stronghold of ISIS in eastern Syria.

The US envoy said that the Coalition was currently stressing the need to block all channels used for financing ISIS and its foreign militants.

Meanwhile, several US media sources said on Thursday that US President Donald Trump’s top advisers on the National Security Council, Col. Derek Harvey resigned from his post. The administration said it is working to identify positions in which his background and expertise can be best utilized.

The sources said Harvey’s decision came after Trump decided to freeze a CIA secret program launched to train the moderate Syrian opposition fighting ISIS.