Medics on Saturday said they are overwhelmed by the hundreds of wounded fleeing Sudan's Darfur region, which has become an increasing focus of global concern more than two months into the country's war.

Residents of the capital Khartoum, hundreds of kilometres (miles) east of Darfur, on Saturday also reported fresh air strikes, gunfire and explosions there in battles between the army and paramilitary Rapid Support Forces (RSF).

Since April 15 when fighting began, the death toll across the country has topped 2,000, the Armed Conflict Location and Event Data Project said.

Up to 1,100 have been killed in the West Darfur state capital El Geneina alone, according to the United States State Department.

The victims included West Darfur Governor Khamis Abdullah Abakar, killed after he criticised the paramilitaries in a Wednesday television interview. The RSF denied responsibility.

"The situation is frankly overwhelming, but everyone is doing their utmost to cope with it", said Seybou Diarra, project coordinator in Adre, Chad for the Doctors Without Borders (MSF) charity.

"As violence rages in West Darfur, wounded people are coming in waves" to the hospital in Adre, just over the border about 20 kilometres (12 miles) west of El Geneina, the MSF statement said.

More than 600 patients, most with gunshot wounds, arrived at the facility over a three-day period -- more than half of them on Friday, it said.

"We are overwhelmed in the operating theatre. We urgently need more beds and more staff," said Diarra, a physician.

According to the International Organization for Migration (IOM), at least 149,000 people have fled from Darfur into Chad.

- 'Ominous reminder' -

They are among the roughly 2.2 million people uprooted nationwide by the fighting which has forced a total of more than 528,000 to seek refuge in neighbouring countries, IOM said.

On Thursday the State Department attributed the atrocities in Darfur "primarily" to the RSF and said the violence and alleged rights violations are an "ominous reminder" of the region's previous genocide.

A years-long war in Darfur began in 2003 with a rebel uprising that prompted then-strongman Omar al-Bashir to unleash the Janjaweed militia, whose actions led to international charges of genocide, war crimes and crimes against humanity.

The RSF have their origins in the Janjaweed.

Along with Darfur, Khartoum has seen the heaviest fighting.

Residents on Saturday reported air strikes around the Yarmouk district -- home to a weapons manufacturing and arms depot complex which the RSF claimed in early June to have seized "full control" of.

The latest strikes caused "civilian victims", a citizens' support committee said.

Residents in Khartoum's south also reported gunfire from "various types of weapons". In the northern suburbs witnesses reported rocket fire and heavy artillery.

A record 25 million people -- more than half the population -- are in need of aid and protection, according to the United Nations, which says it has received only a fraction of the necessary funding.

Saudi Arabia has announced an international pledging conference for Monday in Geneva.