Sudanese President Omar al-Bashir announced the resignation of First Vice-President Ali Taha, state media reported, the first move in a Cabinet reshuffle announced that brought in younger members of the ruling party.
Taha held the country's second-highest political position as first vice president and was the main negotiator of Sudan's Comprehensive Peace Agreement in 2005 that brought an end to the Sudanese civil war.
"[He] resigned to make space for the youth and there are no conflicts between us," state media quoted Bashir as saying on Saturday.
Taha was replaced by Lieutenant General Bakri Hassan Saleh. Bashir held a meeting with ruling National Congress Party leaders to approve the Cabinet reshuffle that introduced at least five ministers from the younger generation of the ruling party.
An hour after midnight on Sunday, an official announced the second vice-president as Hasbo Mohamed Abdulrahman and the parliament head as Alfateh Ezziddin.
Critics of Bashir's regime have become increasingly vocal since the government slashed fuel subsidies in September, leading to the worst urban unrest of his rule.
Security forces are believed to have killed more than 200 demonstrators, and more than 700 were arrested, Amnesty International said, but the government has given a toll of less than half that.
Analysts said the spontaneous protests pointed to an urgent need for change by the Arab-dominated regime grappling with ethnic rebellions in Darfur, South Kordofan and Blue Nile states, dissension within its own ranks, economic crisis and international isolation.
Bashir has since talked of "reform", and repeated a call for a dialogue with all political parties, including armed rebels.
Taha was considered the "first" of two vice-presidents in Bashir's administration.
He led the National Islamic Front party which backed the 1989 coup that installed Bashir.
He later became first vice-president but stepped aside for former rebel leader John Garang in July 2005 - a populist leader from the south that campaigned for a united Sudan - under terms of the peace deal.
After Garang's death in a helicopter crash about a month later Taha continued as second vice-president, but then re-assumed the top deputy's post.
Analysts last year said Taha was a possible successor to Bashir should he step down, while Hassan al-Turabi, who initially supported Bashir and then broke away to form an opposition party, saw rivalry between the president and Taha.