Two soldiers have been killed by security forces as they tried to protect protesters, an opposition-linked group says.

At least two army soldiers have been killed by Sudanese security forces in the capital Khartoum while they attempted to protect protesters in front of the defence ministry, according to an opposition-linked group.

The Sudan Doctors’ Committee, a group affiliated with the opposition, said two soldiers were shot dead early on Tuesday as clashes erupted between government security forces and Sudanese soldiers – many of whom had responded to calls from the people to join anti-government demonstrations.

Eyewitnesses said government forces had attempted to break a sit-in staged by anti-regime protesters outside the army headquarters.

“At around 2:00am, militias riding vehicles of the Rapid Support Forces began attacking protesters,” Ramy Osman, a protester, told Anadolu news agency.

He said attacks escalated two hours later, prompting the army to intervene.

Another protester, who preferred to remain unidentified, said the army had allowed hundreds of protesters to enter the headquarters for protection.

At least seven dead

Thousands of people have been staging a sit-in for four consecutive days outside the complex, which also houses Sudanese President Omar al-Bashir‘s residence, calling for the leader’s resignation.

Since April 6, when the sit-in began, at least seven people have been killed – including the two army soldiers and a protester in Omdurman, Sudan’s second most populous city, the Sudan Doctor’s Committee said.

Chanting “Sudan is rising, the army is rising”, crowds massed undeterred despite attempts to foil the demonstrations.

Forces belonging to the widely-feared National Intelligence and Security Service (NISS) have used tear gas, rubber bullets and live ammunition in a bid to disperse the protesters, according to the Sudanese Professionals Association (SPA), one of the groups spearheading the demonstrations.

The latest rallies are an escalation of the four-month-long campaign for political change.

The protest movement began as a reaction to a government decision to triple the price of bread in December, but it has since escalated into growing demands for al-Bashir’s departure after three decades in office.

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

‘No other option’

Protesters have been appealing for solidarity with the military.

On Monday, the protesting Alliance for Freedom and Change group called on the army to hold direct talks with demonstrators about “forming a transitional government”.

Khalid Omer Yousif, a member of the Sudanese Congress Party, told Al Jazeera from London on Tuesday the opposition alliance was waiting to hear from the military.

“We’re waiting for the army leadership to respond to this initiative because we believe this is the only way out of scenarios that we want our country to avoid,” Yousif said.

According to him, army officers have also joined the protesters.

“They told the protesters that they are backing their demand; they are going to protect them – regardless of the position of the army’s leadership.”

Yousif warned that if the army’s top ranks do not respond to the opposition’s call, then they would be “endangering the unity of the army itself”.

“They have no other option than to respond positively to the demands of the people,” he said.

Defence Minister General Ahmed Awad Ibn Auf had vowed that the army would prevent any slide into disorder.

“Sudan’s armed forces understand the reasons for the demonstrations and is not against the demands and aspirations of the citizens, but it will not allow the country to fall into chaos,” Ibn Auf said on Monday, according to the official SUNA news agency.

In a separate statement, Army Chief of Staff Kamal Abdelmarouf said the military was “discharging its responsibility in securing and protecting citizens.”

Analysts, meanwhile, said senior military figures were eager to “find a way” for Bashir, whose power base is within the armed forces, to step down “gracefully” and initiate a transition of power.

While officials say 38 people have died since the protests erupted on December 19, Human Rights Watch has said at least 51 people have been killed during the demonstrations.