By Ulf Laessing
KHARTOUM, July 26 (Reuters) - Sudan said on Tuesday it was ready to negotiate an end to fighting in its main oil state of South Kordofan but accused armed groups there of trying to prolong the violence by teaming up with rebels in neighbouring Darfur.
Tens of thousands of civilians have fled since clashes flared in June between Sudan's army and fighters, many of them from South Kordofan's ethnic Nuba group.
The United Nations has said Sudan has caused "huge suffering" among civilians by bombing the remote territory, a charge rejected by the army.
"The war is not the will of the people of South Kordofan ... The doors for dialogue and peace are wide open," state governor Ahmed Haroun told reporters in Khartoum.
Sudan has accused the fighters of launching a rebellion inside South Kordofan to try and control the region, and team up with rebels in other areas to challenge the national government.
Activists and some aid workers have accused the Khartoum government of starting the fighting to stamp its authority on the key oil-producing state after the secession of country's south earlier this month. Khartoum has denied the charges.
Southerners voted to declare independence in a referendum that was promised in a 2005 peace deal that ended decades of civil war with the Khartoum government.
South Kordofan, which borders the new country of South Sudan, is home to large groups who fought alongside the south during that civil war and are now seeking greater autonomy inside what remains of Sudan.
Analysts say fighting could spread to other Sudanese states that border the south, chief among them Blue Nile and Darfur, the scene of a separate eight-year insurgency.
Haroun said the South Kordofan fighters were spurred on by Abdelaziz el-Helu, a senior official from the northern branch of South Sudan's governing Sudan People's Liberation Movement (SPLM).
He accused Helu, the SPLM's candidate in the South Kordofan's governorship election in May, of coordinating attacks with Darfur rebels.
"As he exploited the sons of the area to serve South Sudan's goals during the past years, Abdelaziz is now attempting to exploit sons of the area to serve the Darfur rebel movements," he said.
Helu pulled out of the governorship vote and regional government after accusing Khartoum of rigging the elections, charges denied by the north. He was not immediately available for comment on Tuesday.
Haroun is wanted by the International Criminal Court to face charges of masterminding war crimes when he was a government minister during the early stages of the Darfur conflict, which surged in 2003.
Last week, Darfur's most powerful rebel group, the Justice and Equality Movement (JEM) said it had attacked a government position in South Kordofan alongside local fighters. The northern army denied the report.
Events in South Kordofan are hard to verify independently. Aid and U.N. agencies complain they have limited or no access to many areas.
Haroun said authorities were cooperating with aid agencies, adding that life in the state capital Kadugli and other areas had returned to normality.
South Sudan's army has said it no longer has linked with its former fighters in South Kordofan. (Reporting by Ulf Laessing; Editing by Andrew Heavens)