Sudan's paramilitary Rapid Support Forces says its fighters had staged a “surprise” attack on an airbase controlled by the army near the capital, destroying three aircraft and torching large warehouses.
There was no immediate word from the army on Monday's attack on Wad Sayedna airbase near Khartoum's twin city of Omdurman.
Khartoum International Airport, the only other air facility in the greater Khartoum area, was captured by the RSF in the early days of the war with the Sudanese army, which began in April.
An RSF statement said its fighters had destroyed two MiG fighter jets and an Antonov transport plane in the attack.
The airbase is west of Omdurman which, together with the cities of Khartoum and Bahri, comprise the greater capital of Sudan. It was extensively used in the early days of the war to evacuate foreign residents and is believed to have also been used by jet fighters bombing RSF positions.
Witnesses in Omdurman said columns of smoke were rising from the base.
Separately, a video released by the military late on Monday night showed army chief Gen Abdel Fattah Al Burhan walking into what appeared to be a windowless conference room with eight senior officers.
A cheerful and smiling Gen Al Burhan, in camouflage clothing, shook the officers' hands and sat at the head of the table after he handed an automatic rifle to his aide.
Gen Al Burhan has made several public appearances since the war began.
In contrast, his war rival, RSF commander Gen Mohamed Dagalo, has not been seen in public since the early days of the war, fuelling speculation that he may have been seriously injured in battle. Instead, he has been releasing audio recordings, the latest of which was posted online on Monday.
The army has been heavily reliant on air strikes and artillery shelling in its war against the RSF, whose fighters are deployed deep inside residential districts of Khartoum where they are proving difficult to dislodge.
The shelling and air strikes are thought to have contributed significantly to the high number of civilian casualties. The Health Ministry last month said 3,000 civilians had been killed since the war broke out in mid-April, with twice as many injured. The actual figure, however, is believed to be much higher.
The RSF has to date claimed to have shot down about a half dozen army MiG-29 jet fighters.
These claims could not be independently verified, although in some cases the RSF posted footage online purporting to show blackened wreckage of aircraft. The army has never acknowledged the loss of any of its warplanes.
The war in Sudan followed months of tension between the army and the RSF over far-reaching reforms proposed by civilian pro-democracy politicians for the army to withdraw from politics and the paramilitary to be integrated into the armed forces.
The fighting, which is centred in Khartoum, has led to a humanitarian crisis. Three million people have been displaced, of whom more than 700,000 crossed into neighbouring nations in search of a safe haven.
Millions, meanwhile, are trapped in Khartoum, enduring the air strikes, shelling and crossfire, while suffering from lengthy power cuts, water shortages, scarce healthcare services and sharply rising food and fuel prices.
Neither side has shown a genuine appetite for a truce, altogether ignoring or not fully respecting several ceasefires mediated by the US and Saudi Arabia, preferring instead to continue fighting until they gain a clear edge that strengthens their hand if they end up at the negotiating table.
The fighting has continued in the capital, where the army said that on Saturday and Sunday the RSF hit the Medical Corps complex and the military-owned Aliaa hospital in Omdurman.
Aliaa, which treats both military and civilian patients, had also been hosting former dictator Omar Al Bashir, who was transferred there from prison before the start of the conflict.
Beginning on Friday, some of the most intense clashes were seen in Bahri, across the Nile from Omdurman and Khartoum, with the army trying to dislodge RSF fighters.
Gen Dagalo claimed a victory for his forces there in an audio recording posted online on Monday.
“The choice of peace and stability in Sudan has always been and still is our choice … Yet, we are prepared for the choice of war and ready to sacrifice ourselves to ensure a decent life for our people,” said Gen Dagalo, who is better known by his nickname Hemedti.
Reuters contributed to this report
