There have been multiple reports of a military coup in Sudan, with the Information Ministry saying on its official Facebook page that Prime Minister Abdullah Hamdok had been taken away to an unknown location.
Other members of the government are also said to have been detained, according to broadcaster Al-Hadath and the Sudan Tribune news website.
Hamdok had refused to issue a statement of support to the coup leaders, and called for people to go out onto the streets to protest instead, the Information Ministry statement said.
The events could not be verified as communications have been disrupted in Sudan.
Eyewitnesses reported that the Riyadh district of Khartoum was calm in the morning.
A loudspeaker of a local mosque was broadcasting messages calling for civil resistance, the eyewitness said.
Smoke plumes were seen in the sky, apparently from protesters burning tyres. One large thoroughfare nearby was blocked, the eyewitness said.
According to the British organization Netblocks, which documents internet outages worldwide, the internet, mobile phone network and parts of the landline network have been disrupted since the early hours of Monday morning.
The Sudanese government had previously said it was the target of a coup attempt on September 21. Since then, the political situation in Sudan has worsened.
Protests have been going on for weeks, with demonstrators demanding democratic reforms and the withdrawal of the military from the government.
The US special envoy to the Horn of Africa, Jeffrey Feltman, said that Washington is “deeply alarmed at reports of a military takeover” in Sudan.
“This would contravene the Constitutional Declaration and the democratic aspirations of the Sudanese people and is utterly unacceptable,” his statement said.
“As we have said repeatedly, any changes to the transitional government by force puts at risk US assistance,” he added.
Sudan was ruled by Omar al-Bashir for almost 30 years. The long-time strongman was forced out of office in April 2019 after months of mass protests and a military coup.
The military and the civilian opposition then agreed on a joint transitional government to pave the way for elections.