A pledge by the military council that took power in Sudan on Thursday to hand over to a civilian government has been rejected by the country’s main protest group, which said the army was “not capable of creating change”.

The decision by activists to continue fighting peacefully for democratic reform will raise fears of a bloody crackdown. Though the new authorities have so far appeared tolerant of the protests, a senior army officer said on state TV on Friday that “our key responsibility is to maintain public order” and that “we will have zero tolerance for any misdeed in any corner of the country”.

Omar Zain al-Abideen, who is also a member of the military council, said Sudan’s new rulers had no ambition to hold on to power and had intervened to remove President Omar al-Bashir in response to the wishes of the people.

The council wanted to “create an atmosphere to manage a peaceful dialogue”, al-Abideen said. “We are not greedy for power. We are here to guide the country forward and act as a tool for change … We will go sit with the protesters and we hear their ambitions.”

In a statement, the Sudanese Professionals Association, the country’s main protest group, restated its demand for power to be handed immediately to “a transitional civilian government”.

“The SPA has declared its clear position against the military attempt to reproduce the Bashir regime ... [and] sees no alternative other than keeping the struggle against the military coup alive,” it said. “Our endeavour towards getting rid of the regime will continue until the legacy of tyranny is liquidated and its leaders [are] brought to justice.”

Protests in Sudan erupted on 19 December in the eastern city of Atbara after a government decision to triple the price of bread, but quickly evolved into nationwide demonstrations against Bashir’s rule. The situation escalated dramatically on Saturday, when thousands of demonstrators began a sit-in outside the defence ministry compound in central Khartoum.

An association of Sudanese doctors said 26 people had died and more than 150 had been injured – 15 critically – since the sit-in began. Five of the dead were soldiers who were killed protecting the demonstrators during attacks by pro-Bashir militia.

There were also unconfirmed reports of casualties elsewhere in the country, notably in the restive Darfur region.

Ahmed Awad Ibn Auf, right, and his new deputy, Lt Gen Kamal Abdul Murof Al-mahi, after being sworn in on Thursday. Photograph: Reuters Tv/Reuters

Ahmed Awad Ibn Auf, the former defence minister who was sworn in as the head of the council, said on Thursday that it would be in charge for two years, until elections could be held. Auf also announced a three-month state of emergency and an overnight curfew.

The statement prompted anger among demonstrators, who stayed on the streets on Thursday night in defiance of the curfew and into Friday, when, in an apparent attempt to reassure them, the council said it expected the pre-election transition period to last two years at most, or much less if chaos could be avoided. The council also announced that it would not extradite Bashir to face allegations of genocide at the international criminal court. Instead, he could go on trial in Sudan.

The mood in the crowd appeared festive on Friday, with protesters playing music and chanting pro-democracy slogans. Dozens unfurled a large Sudanese flag and shouted “freedom”.

Activists wearing yellow vests controlled traffic around the defence compound and managed foot traffic to and from the sit-in, a witness told Reuters. They also blocked a major bridge in central Khartoum.

At noon thousands of protesters prayed, with members of Sudan’s Christian community holding sheets over them to provide shade in a show of inter-faith solidarity.

There were reports of smaller demonstrations in other towns and cities elsewhere in Sudan.

The US said Khartoum should “exercise restraint and allow space for civilian participation within the government”. The state department spokesman, Robert Palladino, told reporters: “The Sudanese people should determine who leads them … and the Sudanese people have been clear and are demanding a civilian-led transition.”

The EU and the UK urged the army to carry out a “swift” handover to civilian rule and avoid violence.

Bashir was one of Africa’s longest-serving presidents. He is wanted by the ICC on charges of genocide and war crimes for his brutal campaign against insurgents in Darfur, which caused huge suffering to civilians. The UN says 300,000 people have died in the conflict and 2.7 million have fled their homes.

His long rule has left Sudan’s economy in a dire state, with shortages of cash, soaring inflation and very high levels of unemployment.