The U.S. expressed alarm on Monday over an apparent military coup in Sudan, shortly after the Biden administration’s special envoy for the Horn of Africa was in the country encouraging cooperation between civilian and military leaders of Khartoum’s transitional government. 

Thousands of protesters took to the streets after reports emerged that the country's Prime Minister Abdallah Hamdok was detained, with some reports suggesting the leader was put under house arrest, in addition to reports of detention of other senior government officials. 

“The US is deeply alarmed at reports of a military take-over of the transitional government. This would contravene the Constitutional Declaration and the democratic aspirations of the Sudanese people and is utterly unacceptable,” U.S. Special Envoy Jeffrey Feltman said in a tweet. 

“As we have said repeatedly, any changes to the transitional government by force puts at risk U.S. assistance.” 

State Department Spokesperson Ned Price said on Monday that the U.S. was pausing $700 million in economic assistance meant for promoting democracy, in response to the military takeover. 

The U.S. has provided an estimated $377 million in humanitarian assistance for fiscal year 2021, making it the single largest donor of such aid. 

White House Deputy Spokesperson Karine Jean-Pierre told reporters aboard Air Force One on Monday morning that the U.S. rejects "the actions by the military and call for the immediate release of the prime minister and others who have been placed under house arrest.”

She added that "the actions today are in stark opposition to the will of the Sudanese people and their aspirations for peace, liberty, and justice. The United States continues to strongly support the Sudanese people’s demand for a democratic transition in Sudan and will continue to evaluate how best to help the Sudanese people achieve this goal."

Sudan’s top general early Monday morning reportedly announced the dissolution of the transitional civilian-military government, the Sovereign Council, a two-year-old government established in the wake of a popular revolution that overthrew the 30-year military dictatorship of Omar al-Bashir. 

The head of the military, Gen. Abdel Fattah Al-Burhan, reportedly said on national television that disputes between political factions prompted the military to intervene, which he said would run the country while setting up a technocratic government until elections can be held in July 2023. 

“The Armed Forces will continue completing the democratic transition until the handover of the country’s leadership to a civilian, elected government,” he said, according to The Associated Press. 

The general’s announcement was met with criticism by Sudan’s Ministry of Information, the AP reported. It called Burhan’s speech an “announcement of a seizure of power by military coup.”

The European Union’s top diplomat, Josep Borrell, issued a statement on Monday condemning the detention of Sudanese Prime Minister Abdalla Hamdok and other members of the civilian leadership and called on the military to “immediately release those they have unlawfully detained. 

“The actions of the military represent a betrayal of the revolution, the transition, and the legitimate requests of the Sudanese people for peace, justice and economic development,” Borrell said.

United Nations Secretary General Antonio Guterres echoed calls for the release of Hamdok and other civilian government leaders.

"I condemn the ongoing military coup in Sudan. Prime Minister Hamdok & all other officials must be released immediately. There must be full respect for the constitutional charter to protect the hard-won political transition. The UN will continue to stand with the people of Sudan," he tweeted. 

The apparent coup comes just hours after Feltman, the U.S. special envoy for the Horn of Africa, met with political and military leaders of Sudan’s transitional government and expressed support for the continued transition to a full, civilian-led government.

A readout of a meeting between Feltman and Hamdok said that the U.S. side expressed support for “preserving the democratic [civilian] transition process, leading to free and fair elections in which the Sudanese people choose their representatives at the end of the transitional period.”

The readout said Feltman had a joint meeting with Hamdok and the general, Al-Burhan, as well as other top civilian and military leaders. 

Price, of the State Department, told reporters on Monday that Feltman had no indication the military was preparing to launch a takeover.

"To be clear we were not given any heads up about this," he said.

Price said that the State Department is not in a position to make a legal determination of whether a “coup” took place, because the U.S. was already operating under “coup restrictions” since Bashir took power in 1989.

A “coup” designation brings specific limitations on the U.S. in providing assistance to a foreign country, although the designation has an explicit carveout for assistance that aids efforts to promote democracy.

The U.S. was deeply invested in Sudan’s transition from a military dictatorship to a democracy, removing the country from a list of state sponsors of terrorism in 2020 after Khartoum renounced support or ties to designated terrorist organizations, established itself as a partner in counterterrorism and provided compensation to victims of terrorist attacks that Sudan had been alleged to have aided and abetted.

The top lawmakers on the Senate and House committees on foreign relations issued an extraordinary joint statement on Monday condemning the coup and the arrest of the prime minister, cabinet members and other civil society members.

The military takeover “represents the dissolution of the historic political agreement between Sudan’s military leaders and civilian groups that put Sudan on the path towards democratic transition, and threatens progress toward mending our relationship with Sudan in recent years,” the lawmakers wrote.

“The military junta must immediately end the state of emergency, release Prime Minister Hamdok and members of his cabinet unharmed, restore the civilian-led transitional government, and respect the rights of Sudanese citizens to peacefully protest. They must show restraint and safeguard the human rights of all protesters.”

It was signed by Senators Bob Menendez (D-N.J.) and Jim Risch (R-Idaho), the chair and ranking member of the Senate Foreign Relations Committee, and Reps. Gregory Meeks (D-N.Y.) and Michael McCaul (R-Texas), the chair and ranking member of the House Foreign Affairs Committee. 

The removal of the sponsor of terrorism designation also coincided with a pronouncement by Khartoum’s transitional government that it would establish relations with Israel, part of the group of Muslim- and Arab-majority countries signing the Abraham Accords, normalization agreements with Israel that were fostered by the Trump administration. 

The 2019 revolution and overthrow of the Bashir government was viewed as a monumental victory for the will of the popular people in Sudan. But the transition from military rule to a completely democratic, civilian-led government stalled over political fighting. 

Protesters had continued to take to the streets over the inaction of the transitional government and in September, civilian government leaders said they foiled an attempted military coup by Bashir loyalists. 

Morgan Chalfant contributed to this story.

This story was updated at 6:17 p.m.