Sudan's opposition alliance announced on Saturday a 100-day plan for the peaceful overthrow of President Omar al-Bashir, who has been in power for more than two decades.
"I expect the regime will fall before the 100 days finish," said Farouk Abu Issa, who represents more than 20 opposition parties.
He said the first month of the plan includes public forums, including at universities.
They would also ask the state security service for permission to hold a mass rally.
"If we don't get it, then there is another step we can take but we will not announce it now," he told a press conference.
Over the past year, the opposition alliance has pledged to mobilise its members for peaceful protests to topple the government. It has also called for strikes by workers, but there has been no mass response to its appeals despite months of inflation exceeding 40 percent.
Issa said the opposition will also prepare "an initiative for democratic change," including for a transitional administration.
"We are going to send this initiative to the president," he said.
Last June and July, scattered anti-regime protests sparked by inflation spread around the country but later petered out after a security clampdown.
A separate spurt of anti-government rallies occurred in December, when hundreds marched in Khartoum's streets after the death of four students.
On Friday, police fired tear gas after about 200 protesters gathered near a mosque linked to the Umma party, a member of Issa's alliance.
The demonstrators called for the regime's downfall.
The periodic protests against Bashir's 24-year government, which calls itself Islamist, have failed to generate widespread following as did the Arab Spring revolts against authoritarian rulers in North Africa and the Middle East that began in December 2010.
Bashir took power in a 1989 coup that overthrew democratically elected prime minister Sadiq al-Mahdi, the Umma party leader.