Teachers, lawyers, doctors and pharmacists took to the streets of Khartoum and other parts of the country on Tuesday as protests continue against President Omar al-Bashir's rule.
Sudanese police fired tear gas at hundreds of teachers near the education ministry protesting the death of a colleague in detention.
Some demonstrators chanted "freedom, peace, justice", the rallying cry of the protest movement against Bashir's government.
Ahmed al-Kheir, a 36-year-old teacher and member of the Islamist Popular Congress Party (PCP), died in detention after security agents arrested him last week in connection to the protests, a relative told AFP on Saturday.
"Many were carrying photographs of Kheir who died in detention," the witness added.
Kheir was a member of the PCP, which is part of Bashir's government but has called for a probe into the deaths of protesters killed during the rallies.
Groups of doctors, students and lawyers also staged demonstrations in the capital and other areas of the country.
A government decision to triple the price of bread in December sparked initial protests which have spread across Sudan.
Unrest quickly escalated into nationwide rallies against al-Bashir's three-decades in power, with demonstrators demanding the veteran leader step down.
Officials say 30 people have died in protest-related violence since then, but Human Rights Watch says at least 51 people have been killed.
More protests in Khartoum
Police on Tuesday also fired tear gas at a separate demonstration held by graduates of Khartoum University, witnesses said.
"The students were trying to stage a march, but they were dispersed with tear gas," a witness said.
Hundreds of doctors held sit-ins in several hospitals across the country calling on al-Bashir to step down, witnesses said.
Video footage uploaded onto social media showed doctors holding banners calling for Bashir's resignation.
About 200 lawyers held a separate march in Khartoum, but it was swiftly broken up with tear gas, a lawyer said.
"We wanted to give a petition to the chief of the judiciary that calls for freedom of speech and the release of detainees," he told AFP on condition of anonymity.
"But riot police fired tear gas at us, after which we had to disperse."
Amid calls for him to resign, Bashir has remained defiant, addressing loyalists at several rallies across the country and seeking support from regional allies.
On Sunday, he held three gatherings in the state of North Kordofan where he pledged to bolster rural growth by undertaking new infrastructure projects.
Bashir and other senior Sudanese officials have repeatedly said the government can only be changed through elections.
The veteran leader, who came to power following a coup in 1989, is considering running for a third presidential term in polls