* No end to decade-long fighting in Darfur
* Heavy fighting in several parts of western region this week
* Several thousand flee clashes between tribes over gold mine
* Army say repel rebel attack in South Kordofan oil state
More than 30,000 people have fled during two weeks of fighting in Sudan's Darfur region, the United Nations said after some of the worst clashes between government troops, rebels and rival tribes reported there for months.
Conflict has raged in Darfur, a vast arid region in the west of Sudan, since 2003 when mainly non-Arab tribes took up arms against the Arab government in Khartoum, accusing it of political and economic marginalisation.
Fighting between the army and rebels - and divisions among the insurgents - have scuppered years of international mediation and several rounds of peace talks.
Violence has ebbed from the peaks of 2003-4 but has picked up in recent weeks and banditry has also spread.
Around 30,000 people fled their homes in Golo and Guldo towns to escape two weeks of fighting that began on Dec. 24 in the Jebel Marra region, prized for its fertile land, the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said in a report on Friday.
Some 2,800 people fled to a camp in Nertiti in central Darfur, home to already 42,000 displaced people, its report said late on Thursday, citing figures from the government and a community leader.
Rebels from the Sudan Liberation Army (SLA) faction, led by Abdel Wahed Mohamed al-Nur, seized the towns of Golo and Rockero, the international peacekeeping force UNAMID said on Wednesday. The government denied losing the territory and said it had repelled the attacks.
Several thousand people also fled when fighting broke out this week between two Arab tribes in North Darfur over the use of a gold mine, UNAMID said on Friday.
"The fighting has ... resulted in a number of casualties, looting, burning of nearby villages, and the displacement of thousands of civilians forced to flee towards Kabkabiya, Saraf Omra and Al Sereif towns," UNAMID said in statement.
Three UNAMID planes evacuated 26 wounded people, it said, adding that the number of dead was unclear because tribesmen had banned a patrol visiting the area of Jebel Amer, where the mine is located.
On another front, in Sudan's main oil-producing state of South Kordofan, Sudan's army said it had repulsed an attack from rebels of the Sudan People's Liberation Movement-North (SPLM-North), state news agency SUNA said.
South Kordofan borders Darfur and rebels from both regions, who all complain of government discrimination, have formed a alliance vowing to topple Sudanese President Omar Hassan al-Bashir.
Armed forces spokesman al-Sawarmi Khalid said SPLM-North forces had attacked the army in the area of al-Hamra. "Fifty of their forces were killed," he said.
Yasir Arman, one of the exiled leaders of the SPLM-North, declined to comment, telling Reuters he needed to check first with the military command on the ground.
Events in Darfur and South Kordofan are hard to verify as Sudan restricts travel by journalists and diplomats.
The International Criminal Court has issued arrest warrants for Bashir and other Sudanese officials to face charges of masterminding war crimes in Darfur. They deny the charges and refuse to recognise the court.
Human rights groups and the United Nations estimate that hundreds of thousands of people have died in Darfur's conflict, although the toll is disputed by the government, which says around 10,000 people have been killed.