KHARTOUM — Members of Sudan's transitional government and other civilian leaders have been arrested amid reports of a military coup.

Prime Minister Abdallah Hamdok is among those reported to have been put under house arrest by unidentified soldiers.

Pro-democracy protesters have taken to the streets of the capital, Khartoum.

Military and civilian leaders have been at odds since long-time ruler Omar al-Bashir was overthrown two years ago and the transitional government set up.

Video footage from the north African nation's capital on Monday showed protesters manning lit barricades and entering the area near the military's headquarters, with soldiers looking on.

No-one in the military has commented so far and it remains unclear who was behind the pre-dawn arrests.

A statement from the information ministry on Facebook said the detentions were carried out by "joint military forces" and those arrested were being held in "an unidentified location".

The ministry said soldiers had stormed the HQ of the state broadcaster, in Omdurman, and detained staff there.

It also said Hamdok was being pressed to support a coup but was refusing to do so and he urged people to continue with peaceful protests to "defend the revolution".

The United States was "deeply alarmed" by the coup reports, its special envoy for the Horn of Africa, Jeffrey Feltman, said. The UN, EU and Arab League also expressed deep concern.

Witnesses say the internet is down and that army and paramilitary troops have been deployed across the city. Khartoum airport is now closed, and international flights are suspended.

Sudan's main pro-democracy group has called on its supporters to resist any military coup.

The Sudanese Professionals’ Association, Sudan’s main pro-democratic political group, said there were internet and phone signal outages across the country.

The group said at least five senior government officials had been detained, and called on people to take to the street to counter an apparent coup.

The arrests comes after weeks of rising tensions between Sudan’s civilian and military leaders.

A failed coup attempt in September fractured the country along old lines, pitting more conservative Islamists who want a military government against those who toppled Bashir in mass protests. In recent days, both camps have taken to the street in demonstrations.

A possible takeover by the military would be a major setback for Sudan, which has grappled with a transition to democracy since Bashir's ouster.

The arrests of the government figures were confirmed by two officials who spoke on condition of anonymity because they were not authorised to speak to the media.

The officials said the detained government members include Industry Minister Ibrahim al-Sheikh, Information Minister Hamza Baloul, and Mohammed Al-Fiky Suliman, member of the country's ruling transitional body, known as The Sovereign Council, and Faisal Mohammed Saleh, a media adviser to Prime Minister Abdalla Hamdok.

Earlier reports said the whereabouts of Hamdok were not immediately clear, amid media reports that security forces were stationed outside his home in Khartoum. Photos circulating online showed men in uniform standing in the dark, allegedly near his home.

Ayman Khalid, governor of the state containing the capital, Khartoum, was also arrested, according to the official Facebook page of his office.

The arrests followed meetings the US special envoy for the Horn of Africa Jeffrey Feltman had with Sudanese military and civilian leaders Saturday and Sunday in efforts to resolve the dispute. Sudan's state news website highlighted the meetings with military officials.

NetBlocks, a group which tracks disruptions across the internet, said it had seen a “significant disruption” to both fixed-line and mobile internet connections across Sudan with multiple providers early Monday.

“Metrics corroborate user reports network disruptions appearing consistent with an internet shutdown,” the advocacy group said. “The disruption is likely to limit the free flow of information online and news coverage of incidents on the ground.” — Agencies