Chanting "Sudan is rising, the army is rising," crowds of men and women massed outside the complex that also houses Bashir's official residence and the defence ministry, many of them having spent the night there.
Thousands of Sudanese protesters rallied outside the army's headquarters in the capital Sunday for a second day calling on the military to back them in demands that President Omar al-Bashir resign as police fired tear gas to disperse them.
Chanting "Sudan is rising, the army is rising," crowds of men and women massed outside the complex that also houses Bashir's official residence and the defence ministry, many of them having spent the night there, witnesses said.
"After what we did yesterday, we will not leave this area now until our mission is accomplished," said protester Osama Ahmed, who spent the night outside the compound.
"We won't leave this area until he steps down," he said, referring to Bashir.
Protesters whistled and waved at military vehicles entering the compound, prompting some soldiers to wave back, a day after demonstrators said they were gathering to ask the army to "come join us".
Riot police deployed near the complex Sunday morning, firing tear gas to disperse the crowds.
At least 5 killed
Organisers say security forces killed at least five protesters in the last 24 hours.
Sarah Abdel-Jaleel, a spokeswoman for the Sudanese Professionals Association said on Sunday that four people were killed in the capital city of Khartoum when security forces tried to disperse crowds approaching the military's headquarters.
Abdel-Jaleel says another protester was killed in Khartoum's twin city of Omdurman.
International rights groups say at least 60 people have been killed since protests began.
Protest organisers chose April 6 to begin the rally outside the army headquarters to mark the 1985 uprising that toppled the then regime of president Jaafar Nimeiri.
Ahead of the demonstration, organisers had urged the army to either "take the side of the people or the dictator's".
Chanting the movement's catchcry "freedom, peace, justice", thousands of men and women marched through the streets of the capital Saturday, reaching the fortified army complex for the first time since anti-government protests first broke out.
The rally was the biggest yet since protests erupted on December 19 in the central town of Atbara, quickly spreading to the capital and towns and cities across the country.
Rally organisers on Sunday urged the demonstrators to continue with their sit-in outside the army complex.
"We call on our people from areas near Khartoum to join those who are at the army headquarters," the organisers said in a statement.
Since the start of the protests, security agents and riot police have cracked down on demonstrators but the army has not intervened.
Witnesses said groups of women, men and children were walking towards the complex from several parts of the capital.
Some protesters blocked a nearby bridge linking Khartoum with the northern Bahari district with rocks causing huge traffic jams, onlookers said.
Outside the army complex, protesters sang nationalist songs, whistling and clapping as they pressed on with the rally.
Several private companies declared a holiday at their offices, while some arranged to ferry water, snacks and juice to the protesters, according to witnesses.
Rallies over bread prices quickly morphed into protests against Bashir's government, with demonstrators accusing it of mismanaging the economy, leading to soaring food prices and regular shortages of fuel and foreign currency.
Bashir has acknowledged that the economic concerns raised by protesters are "legitimate", but he imposed emergency rule on February 22 after an initial crackdown failed to rein in the protests.
The scale and intensity of protests have shrunk since the emergency rule went into effect.
But with Saturday's rally analysts say the protest movement has gained new momentum.
"The scale of protests on Saturday illustrate that Bashir's gamble that he can save his regime through repression is proving to be a losing bet," said Murithi Mutiga of the International Crisis Group.
Bashir, wanted by the Hague-based International Criminal Court for alleged war crimes and genocide in conflict-wracked region of Darfur, swept to power in an Islamist-backed coup in 1989.
The veteran leader has remained defiant, introducing tough measures that have seen protesters, opposition leaders, activists and journalists arrested.