"According to humanitarian organisations, so far in 2013 at least 460,000 people have fled their homes in Darfur as a result of inter-tribal fighting and clashes between the SAF (Sudanese army) and armed movements," the UN Office for the Coordination of Humanitarian Affairs said in its weekly bulletin.
"This is more than the number of people internally displaced in Darfur in 2011 and 2012 combined," OCHA said.
The latest figure marks a jump from the 300,000 who UN humanitarian aid chief Valerie Amos announced in May had been displaced during the first five months of the year.
The African Union-UN peacekeeping mission in Darfur (UNAMID) has also said inter-ethnic fighting has become Darfur's major source of violence.
More From This Section
Most recently, Arab militias used rockets, artillery and heavy machineguns in battle across a wide swathe of southwest Darfur on Sunday, sources in the warring Taisha and Salamat tribes told AFP.
The Salamat have been fighting off-and-on with the Misseriya, a Taisha ally, in southwest Darfur since April.
There was no information on casualties from Sunday's battle, sparked by a land dispute.
That brings to more than 200 the number of casualties from fighting between the two tribes since April.
Non-Arab rebels rose up 10 years ago in Darfur, seeking an end to what they viewed as Arab elites' domination of Sudan's power and wealth.
In response, government-backed Janjaweed militiamen shocked the world with atrocities against civilians.
Analysts say the cash-starved government can no longer control its former Arab tribal allies, whom it armed against the rebellion, and violent competition for resources has intensified.