Sudanese authorities said they arrested scores of members of the former ruling party, accusing them of plotting "acts of destruction", as young people took to the streets in separate pro-democracy protests in the capital.
Police detained at least 200 members of the National Congress Party (NCP) early on Wednesday, officials said, the 32nd anniversary of the coup that brought that party's former leader, ex-President Omar al-Bashir, to power.
Bashir was in turn ousted in 2019 and replaced by a shaky military-civilian transitional government that has promised to hold elections and has regularly accused NCP loyalists of trying to undermine its work and disrupt the country.
"There were groups from the National Congress Party preparing for acts of destruction," said Salah Manaa, a member of the official committee set up to dismantle the remnants of Bashir's political and economic networks.
Sudan's civilian prime minister, Abdalla Hamdok, warned earlier this month about the potential for chaos and civil war stoked by the former administration.
Underlying the competing pressures facing the transitional government, pro-democracy protesters marched in the capital Khartoum and across the Nile in Omdurman, marking a different anniversary on Wednesday.
Two years ago, massive protests that raged across the capital and country pushed the military leaders who ousted Bashir to begin negotiating with civilians, ending in Sudan's current power-sharing arrangement.
Police fired tear gas both at the protesters chanting anti-Bashir and pro-democracy slogans, as well as at about 150 NCP loyalists protesting against the transitional government in central Khartoum.
The new military-civilian administration has sought keep the fractured country together and rebuild links with the West since Bashir's exit. On Tuesday, the IMF cleared Sudan to begin to seek relief on about $56 billion in debt.
But many of the economic crises that fueled public anger against Bashir's rule have persisted since he left.
Manaa's committee said authorities had tracked large money movements linked to the alleged plot, and recently arrested dozens of illegal currency traders suspected of working to sabotage the economy.
There was no immediate statement issued by any of the arrested people, or by lawyers representing them. The NCP was banned in 2019.