Khartoum - Rebels in Sudan's Darfur region said on Sunday they had shelled a state capital, in a rare attack on the government stronghold where international peacekeepers are also based.
The government did not immediately comment on the report and the claim could not be immediately independently verified.
War has ravaged Darfur since rebels took up arms in 2003, complaining the central government had neglected the region. The United States and the International Criminal Court accuse Sudan's government of genocide, crimes against humanity and war crimes in Darfur.
Conflict has continued despite the presence of the world's largest peacekeeping operation and many attempts to broker peace by the United States, Qatar and others.
On Saturday, insurgents fired Katyusha rockets and other heavy weapons at El Fasher, capital of North Darfur state, rebel spokesman Gibreel Adam Bilal said.
Bilal said the rebels aimed to destroy El Fasher's air base in retaliation for government air strikes and attacks by pro-government militias in northern Darfur.
"We cannot just keep in our areas waiting for the air force to attack us," he said.
Fighters from powerful rebel groups the Justice and Equality Movement and the Sudan Liberation Army, loyal to Minni Minnawi, took part in the attack, Bilal said.
Sudanese newspaper al-Intibaha reported that three rockets landed about seven kilometres (four miles) west of El Fasher.
The African Union-United Nations mission in Darfur (UNAMID), which has its headquarters in El Fasher, said it had reports of gunfire near El Fasher, which it said was not unusual.
There were no casualties according to the reports, UNAMID spokeswoman Aicha Elbasri said in an emailed statement.
A separate rebel group allied to the Darfur insurgents shelled the main city of the oil-producing South Kordofan state on Friday during a visit of Sudan's defence minister, rebels and residents said.
The United Nations and others have said hundreds of thousands of people may have died in the Darfur conflict. The government has put the toll at around 10 000.
Qatar brokered a deal between Khartoum and one rebel group last year, but the most powerful insurgents refused to join.
Instead, they announced an alliance with rebels in southern states on the border with South Sudan, which seceded last year.
The Sudanese Revolutionary Front, as the alliance is called, says it is committed to overthrowing Sudan's President Omar Hassan al-Bashir.
The International Criminal Court has indicted Bashir and other officials for war crimes in Darfur, which they deny.