* Weeks of clashes force 100,000 to flee
* Numbers sharply higher than previous estimates
* Dozens of villages burned in gold mine dispute (Adds background)
KHARTOUM, Jan 16 (Reuters) - A surge in violence in Sudan's strife-torn Darfur region has killed more than 100 people and forced 100,000 to flee, the United Nations said on Wednesday, sharply increasing its estimates after weeks of clashes.
Fighters caught up in a dispute over control of a gold mine had set fire to around three dozen villages in the north of the region, the U.N. Humanitarian Coordinator in Sudan, Ali Al-Zatari, said in a statement.
More than 100 people had died and around 70,000 people had been displaced by the fighting between rival Arab tribes that broke out in the Jebel Amer area last week, he added.
Another 30,000 people had left their homes after separate fighting between the army and a rebel group in the central Jebel Marra area that started late in December, the U.N. said.
Conflict has raged in vast arid region for almost a decade since mainly non-Arab tribes took up arms against the Arab government in Khartoum in 2003, accusing it of political and economic marginalisation.
Violence overall has ebbed since the massacres reported in the early days of the uprising. But the latest clashes have been some of the worst in the area for months.
"The largest concentration of displaced people is in El Sireif where thousands of people are in urgent need of food, water, shelter and medical attention," Zatari said in the statement.
Last week the United Nations said the gold mine dispute and the Jebel Marra fighting had displaced a total of 30,000 people.
Events in Darfur are hard to verify as Sudan restricts travel by journalists, aid workers and diplomats.
Rebel divisions and a string of broken ceasefires have scuppered years of international mediation and several rounds of peace talks. Banditry has also spread.
The International Criminal Court has issued arrest warrants for Sudan's President Omar Hassan al-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 hundreds of thousands of people have died in Darfur's conflict. The government says around 10,000 people have been killed. (Reporting by Ulf Laessing; Editing by Andrew Heavens)