Sudanese security forces detained three prominent pro-democracy figures overnight, their relatives and other activists said Wednesday, as internal and international pressure mounted on the country's military following its coup.

The arrests came as protests denouncing Monday’s takeover continued in the capital of Khartoum and elsewhere, and many businesses shut in response to calls for strikes. The coup threatens to halt Sudan’s fitful transition to democracy, which began after the 2019 ouster of longtime ruler Omar al-Bashir in a popular uprising.

Groups of protesters — in some places, dozens, in others, hundreds — set up barricades of stones on main roads throughout the day. Security forces waded in, chasing demonstrators and dismantling the barriers.

“It looks like a hit-and-run process, they remove, and we build,” activist Nazim Sirag said.

Some protesters were shot and wounded, activists said, though they did not have exact figures. Security forces confronting demonstrators have killed at least six people since Monday and wounded over 140 others, many in critical condition, according to physicians with the Sudan Doctors’ Committee.

Read: Sudan's military takes power in coup, arrests prime minister

Prominent rights defender Tahani Abbas said the pro-democracy movement would continue street protests despite the crackdown.

“We are frustrated,” she said, “but we have no other option but the street.”

In a nod to deteriorating security conditions, the State Department authorized nonessential personnel and the families of all government employees at the U.S Embassy in Khartoum to leave Sudan “due to civil unrest and possible supply shortages.”

The coup came after weeks of mounting tensions between military and civilian leaders over the course and pace of Sudan's moves toward democracy.

The African Union suspended Sudan — an expected move typically taken in the wake of coups. The AU Peace and Security Council said via Twitter on Wednesday that the suspension would remain in place “until the effective restoration of the civilian-led Transitional Authority,” as the deposed government is known.

The AU plans to send a mission to Sudan to hold talks with rival parties.

The World Bank also suspended disbursements for its operations in Sudan, whose economy has been battered by years of mismanagement and sanctions and was dealt a blow when the oil-rich south seceded in 2011 after decades of war, taking with it more than half of public revenues and 95% of oil exports.

“We hope that peace and the integrity of the transition process will be restored, so that Sudan can restart its path of economic development and can take its rightful place in the international financial community,” bank President David Malpass said in a statement.

Prime Minister Abdalla Hamdok's now-deposed government had embarked on a series of reforms meant to transform the country’s economy and have the nation rejoin the international community after over two decades of isolation under al-Bashir.

In May, the World Bank said it had allocated $2 billion to Sudan to finance big infrastructure projects along with others over the next 12 months, after the U.S. provided bridge financing of $1.15 billion to Cleese Sudan’s overdue payments to the global financing body.

Following widespread international condemnation, the military allowed Hamdok and his wife to return home on Tuesday night. Hamdok, a former U.N. economist, was detained along with other government officials when the military seized power.

Several Western embassies in Khartoum said Wednesday they will continue to recognize Hamdok and his Cabinet as “the constitutional leaders of the transitional government” of Sudan.

In a joint statement, the embassies of the European Union, the U.S., the U.K., France and several other European countries called for the release of other detained officials and for talks between the military and the pro-democracy movement.

EU foreign affairs chief Joseph Borrell tweeted that he spoke with Hamdok on Wednesday to voice his support for the return of a civilian-led transitional government as “the only way forward.”

Read: PM, officials detained, internet down in apparent Sudan coup

“We don’t want Sudan to go back to dark hours of its history,” he said.

U.S. Secretary of State Antony J. Blinken also spoke with Sudanese Foreign Minister Mariam al-Mahdi about how to support the civilian-led transition to democracy, and condemned the military takeover.

The general leading the coup, Abdel-Fattah Burhan, has pledged to hold elections, as planned, in July 2023, and to appoint a technocrat government in the meantime.

Burhan met Wednesday with Saudi Ambassador Ali Hassan bin Ghafar to discuss “efforts to resolve the crisis through consultations with all concerned parties,” the Sudanese military said.

But critics doubt the military is serious about eventually ceding control, noting that the coup came just weeks before Burhan was supposed to hand over the leadership of the top ruling body, the Sovereign Council, to a civilian. The council, which was made up of both civilian and military leaders but led by a general, was the ultimate authority in the country, while Hamdok’s transitional government ran day-to-day affairs. Both were dissolved in the coup.

Volker Perthes, the U.N. special envoy for Sudan, met Wednesday with Burhan and reiterated the U.N.’s call for a return to the transition process under the constitutional document and the immediate release of all those arbitrarily detained.

Perthes also met Hamdok in his residence “where he remains under guard,” U.N. spokesman Stephane Dujarric said.

The activists taken overnight were Ismail al-Taj, a leader of the Sudanese Professionals’ Association, the group at the forefront of the protests that brought down al-Bashir; Sediq al-Sadiq al-Mahdi, a leader in Sudan’s largest political party, known as Umma and brother of Foreign Minister Mariam al-Mahdi; and Khalid al-Silaik, a former media adviser to the prime minister.

The three have been outspoken critics of the military takeover and have called for protests. Already, tens of thousands of Sudanese have taken to the streets, and activists are planning a mass demonstration on Saturday.

Al-Silaik was detained moments after he gave an interview to broadcaster Al-Jazeera, according to his wife, Marwa Kamel. In the interview, he criticized the military’s takeover, calling Hamdok and his government the legitimate administration of Sudan.

“What Gen. Burhan did is a complete coup. ... People will respond to this in the coming days,” al-Silaik said.

Activists Nazim Siraj and Nazik Awad and the Umma party confirmed the arrests of the other two figures.

When Burhan dissolved the Sovereign Council and the transitional government on Monday, he alleged that the military was forced to step in to prevent the country from sliding into civil war. But he had repeatedly warned he wanted to delay the transition to civilian leadership of the council.

Meanwhile, flights in and out of Khartoum’s international airport resumed Wednesday, a day after the country’s Civil Aviation Authority said they would be suspended until Oct. 30.