WASHINGTON (AP) — US special operations forces carried out a precarious evacuation of the American embassy in warring Sudan on Sunday, sweeping in and out of the capital, Khartoum, with helicopters on the ground for less than an hour. No shots were fired and no major casualties were reported.

With the last US employee of the embassy out, Washington shuttered the US mission in Khartoum indefinitely. Left behind were thousands of private American citizens remaining in the east African country.

US officials said it would be too dangerous to carry out a broader evacuation mission. Battles between two rival Sudanese commanders entered their ninth day Sunday, forcing continued closing of the main international airport and leaving roads out of the country in control of armed men. Fighting has killed more than 400 people.

In a statement thanking the troops, President Joe Biden said he was receiving regular reports from his team on efforts to assist remaining Americans in Sudan “to the extent possible.”

He also called for the end to “unconscionable” violence there.

About 100 US troops in three MH-47 helicopters carried out the operation. They airlifted all of roughly 70 remaining American employees from a landing zone at the embassy to an undisclosed location in Ethiopia. Ethiopia also provided overflight and refueling support, said Molly Phee, assistant secretary of state for African affairs.

Biden had ordered American troops to evacuate embassy personnel after receiving a recommendation from his national security team, with no end in sight to the fighting.

“This tragic violence in Sudan has already cost the lives of hundreds of innocent civilians. It’s unconscionable and it must stop,” Biden said. “The belligerent parties must implement an immediate and unconditional ceasefire, allow unhindered humanitarian access, and respect the will of the people of Sudan.”

Sudan’s fighting broke out April 15 between two commanders who just 18 months earlier jointly orchestrated a military coup to derail the nation’s transition to democracy.

The ongoing power struggle now between the armed forces chief, Gen. Abdel-Fattah Burhan, and the head of the Rapid Support Forces paramilitary group, Gen. Mohammed Hamdan Dagalo, has millions of Sudanese cowering inside their homes, hiding from explosions, gunfire and looting.

The violence has included an unprovoked attack on an American diplomatic convoy and numerous incidents in which foreign diplomats and aid workers were killed, injured or assaulted.

An estimated 16,000 private U.S. citizens are registered with the embassy as being in Sudan. The figure is rough because not all Americans register with embassy or say when they depart.

The embassy issued an alert earlier Saturday cautioning that “due to the uncertain security situation in Khartoum and closure of the airport, it is not currently safe to undertake a U.S. government-coordinated evacuation of private US citizens.”