Thousands of people held a sit-in outside Omar al-Bashir’s residence in central Khartoum on Sunday, having camped there overnight after the biggest demonstration in months of protests against his 30-year rule, witnesses said.

There have been sustained protests against the Sudanese president and his National Congress party since 19 December. Security forces have fired teargas, stun grenades and live bullets to disperse protesters and dozens have been killed during demonstrations.

Bashir has refused to step down, saying that his opponents need to seek power through the ballot box.

Sudan suffered a total power blackout on Sunday, the ministry of water resources, irrigation and electricity said without giving an explanation for the outage. Electricity was later restored in some areas.

Since the sit-in began on Saturday, security forces have fired teargas several times in an attempt to clear the protesters, but thousands remained.

Apparently emboldened by the success of similar but much larger protests in Algeria, which forced ailing president Abdelaziz Bouteflika to step down last week, Sudanese activists called for Saturday’s protests. The demonstrations marked the anniversary of the 1985 military coup that overthrew autocratic president Jaafar Nimeiri after mass protests against his rule.

The protesters urged the military to side with them once more in their bid to push Bashir out of power.

Apart from Bashir’s residence, the compound – the most heavily guarded in Sudan – also houses the defence ministry and the headquarters of the powerful National Intelligence and Security Service. Thousands of protesters also gathered in Khartoum’s Burri neighbourhood on Sunday, where they blocked several main roads, witnesses said.

On Saturday at least one person died during protests in Omdurman, across the Nile from Khartoum, state news agency Suna said without providing detail on the cause of death. The person killed was a laboratory doctor, according to a statement from an opposition doctors’ committee. Medical staff have played a prominent role in the protests.

Suna said other civilians and police officers were wounded on Saturday in Omdurman, the scene of protests late into the evening that subsided by Sunday morning.

The sit-in outside the compound appeared to mirror the 2011 Arab spring protests, in which demonstrators in Cairo and other Arab capitals camped out in public squares for days to demand a change in rule.

Police and security forces on Saturday blocked all bridges leading to the capital’s centre from Khartoum North and Omdurman, across the Nile to the north and west respectively, in what appeared to be a bid to prevent the sit-in from swelling.

They remained closed on Sunday, causing major traffic jams. Hundreds of people were crossing into Khartoum from Omdurman via Victory Bridge by foot on Sunday morning, a witness said, as cars were at a standstill for hours.