"The government are in Disa and Birmaza now," said Ibrahim al-Hillo, a commander from the SLA faction headed by Abdel Wahid Mohammed Nur, an exiled leader.
"There is isolated shooting, but the Antonov planes are overhead many times in the day and they have been bombing," he added, declining to say how many casualties there might be.
Fighters from the SLA remained close to the towns but government forces now controlled them, with civilians fleeing into the surrounding desert, he said.
His account could not be independently verified with other sources.
"The civilians have run away into the desert or are hiding in the trees," he added, speaking from close to Disa.
"The situation is very bad. It's raining and the people are suffering very much."
Fighting around Tawila - where rebels reported heavy clashes on Saturday and Sunday - has also ceased, according to field commanders, said Al-Hillo.
Government forces were now encamped there, he said.
There was no response from the military. But in comments made to Sudanese media on Monday, an army spokesman said troops were in control of areas in eastern Jebel Marra, south of Tawila in West Darfur state.
No mention was made of fighting elsewhere.
The joint African Union-UN peacekeeping mission in Darfur, or Unamid, said reports from North Darfur state indicated the government had launched "general attacks".
Around 120 Land Rovers and trucks carrying "heavily armed" government troops were spotted near Malha, around 180km northeast of the reported fighting at Disa and Birmaza, the force said on Sunday.
Two attack helicopters had landed at Kutum, some 70km south of the two towns, Unamid said in a statement.
The Arab League ministerial council, meanwhile, is to form an Arab ministerial committee to arrange peace talks in Qatar between the Sudanese government and armed groups in Darfur.
Sheikh Hamad bin Jassim bin Jaber Al Thani, Qatar’s prime minister and foreign minister, will head the committee.
Others on the committee will include Amr Musa, the Arab League secretary general, and Jean Ping, the chairperson of the African Union commission, to head the committee.
The UN says up to 300,000 people have died and more than 2.2 million fled their homes since the conflict erupted in February 2003. Sudan says 10,000 have been killed.
The war began when ethnic minority rebels took up arms against the Arab-led Khartoum regime and state-backed Arab militias, fighting for resources and power.
The conflict has since deteriorated with the emergence of a multiplying array of rebel groups, breakaway militia groups and bandits.