U.S. Secretary of State Antony Blinken expressed his grave concern over reports of rising hostilities between the Sudanese Armed Forces and the major paramilitary organization in the nation, the Rapid Support Forces, and demanded an immediate end to the fighting.

The situation in Khartoum was called “fragile” by Blinken.

“We are in touch with the Embassy team in Khartoum – all are currently accounted for,” Blinken wrote on Twitter. “We urge all actors to stop the violence immediately and avoid further escalations or troop mobilizations and continue talks to resolve outstanding issues.”

The Rapid Support Forces said on Saturday it had taken control of the presidential palace, the residence of the army chief and Khartoum international airport on Saturday in an apparent coup attempt.

In response to a question during a press conference in Hanoi, Vietnam, Blinken said the major parties in Khartoum had reached a very important framework agreement on how to proceed with a transition to civilian government some weeks ago.

There had been progress, though there were still some important issues that needed to be dealt with, he added.

“But I think there’s a real opportunity to move forward on the agreed framework, and certainly that’s what we’re strongly supporting,” said Blinken.

“It’s a fragile situation. There are other actors that may be pushing against that progress. But this is a real opportunity to finally carry forward the civilian-led transition, and one that we and other countries are trying to bolster.”