Military head Gen Abdel Fattah Al Burhan announced the dismissal of the government and a national state of emergency and said the military would be taking control until a new government of technocrats could be formed to rule under the direction of the army.
Here is everything you need to know about what has happened in Sudan and who is involved:
Who is in charge of Sudan?
Sudan began its transition to democracy after a popular uprising that led to the removal of long-time president Omar Al Bashir in April 2019, ending his 29-year rule.
Al Bashir, who is in jail, is wanted by the International Criminal Court to face charges of war crimes in the western Sudanese region of Darfur.
After four months of protests in 2018-2019 led by the Forces of Freedom and Change (FFC), a pro-democracy alliance, Al Bashir was removed by the army.
A power-sharing deal between the FFC and the military was agreed in August 2019 and the Sovereign Council, led by Gen Abdel Fattah Al Burhan, was formed to oversee a "transitional government" until elections in 2023.
According to the deal, the military is in charge of the first rotational phase of the transitional government and they were due to hand over to a civilian leader next month for the second phase.
Monday's arrests came after weeks of tension between the military and their civilian partners.
Internet activity tracking website NetBlocks reported cuts to services in Sudan on Monday morning and residents told The National they could not get online. Internet cuts were common during the 2018-2019 uprising and were used to prevent public gatherings from growing.
Who is Gen Abdel Fattah Al Burhan?
Gen Al Burhan on Monday announced a state of emergency across the country and dissolving the transitional government.
Mr Al Burhan is an armed forces veteran who flew under the radar until he was assigned a senior role under Al Bashir's government.
Born in 1960 to a Sufi family in the village of Gandatu, north of Khartoum, Gen Al Burhan studied in the Sudanese army academy and later in Egypt and Jordan. He is married and has three children.
What is the military's role?
Although the military's role is supposed to be largely honorary, civilians have repeatedly complained of its overreach in foreign policy and peace negotiations.
The military has accused civilian parties of mismanagement and monopolising power. A coalition of rebel groups and political parties have recently aligned themselves with the armed forces and have campaigned to dissolve the civilian-led Cabinet.
In September, authorities said they foiled an attempted coup. Al Bashir loyalists were behind the move, they said.
One of the sore spots involves bringing Al Bashir to justice over his involvement in the Darfur conflict in the early 2000s. The military and the government were at odds over whether to hand him over to the ICC for trial, with the generals reluctant to do so.
The Cabinet has signed off on handing over suspects, but the Sovereign Council, with its military leaders, has not.
Another issue of contention is an investigation into the killings of pro-democracy protesters on June 3, 2019, in which military forces are implicated for violently dispersing a protest sit-in outside the military headquarters in Khartoum.
Activists and civilian groups have been angered by delays in making the findings of the investigation public.
Civilians have also pushed for oversight and restructuring of the military, particularly through the integration of the powerful paramilitary Rapid Support Forces.
What led to Al Bashir's downfall?
A worsening economic crisis that sent the currency plunging and created frequent shortages of bread and fuel was the trigger for Al Bashir's downfall.
The transitional government has introduced rapid reforms monitored by the International Monetary Fund in a successful effort to secure debt relief and attract foreign financing.
This came after Mr Hamdok led efforts to remove Sudan from the US list of state sponsors of terrorism, opening the country up for investment and improving its standing among the international community.
After the reforms were introduced, inflation rose to historic highs of more than 400 per cent and many Sudanese have complained of struggling to get by. There have been occasional protests against economic conditions.
What about Sudan's neighbours?
Sudan is part of a volatile region, bordering the Red Sea, the Sahel and the Horn of Africa. Several of its neighbours, including Ethiopia, Chad and South Sudan, have been affected by political upheaval and conflict.
Since late last year, conflict in Ethiopia's Tigray region has pushed tens of thousands of refugees into eastern Sudan and caused tension in disputed agricultural lands along the border.
Sudan is pushing, with Egypt, for a binding deal over the operation of a hydropower dam Ethiopia is building near the Sudanese border.
Talks have stalled but Ethiopia has started filling the reservoir behind the dam, which Sudan says could put its people, dams and water centres at risk.