KHARTOUM, Dec 9 (Reuters) - Sudan's army said on Thursday it attacked the only Darfur rebel group that signed a 2006 peace deal saying it planned to join forces with rebels still fighting the government, dealing a heavy blow to the struggling accord.
The Sudan Liberation Movement led by Minni Arcua Minnawi signed the internationally-brokered Darfur Peace Agreement with Sudan's government in the Nigerian capital Abuja in May 2006.
But the deal was boycotted by Darfur's two other main rebels forces and did nothing to end the fighting and banditry in the remote western region.
"There were clashes and we defeated them yesterday," Sudan's army spokesman al-Sawarmi Khaled said. "They were heading south and we attacked them. They have many wounded."
Last week Khaled said SLM forces were moving towards south Sudan, a semi-autonomous region which fought its own civil war with Khartoum and is expected to secede next year.
He said the SLM planned to join forces with rebels still fighting the government and declared the SLM a military target.
Minnawi's group was not immediately available to comment but has previously said any attack on their forces would be a "declaration of war."
After April elections, Minnawi was not reappointed presidential assistant -- a post he won under the 2006 accord -- and has been living in south Sudan's capital Juba for months.
U.N.-African Union peacekeepers (UNAMID) said they had received reports of the clashes in South Darfur state, close to the border with south Sudan, but could give no further details.
The United Nations estimates some 300,000 people died in the humanitarian crisis sparked after Khartoum launched a brutal counter-insurgency campaign in 2003 against Darfur rebels demanding more of a share in wealth or power.
The International Criminal Court is demanding President Omar Hassan al-Bashir's arrest to face charges of war crimes and genocide in Darfur, but Khartoum rejects the court's jurisdiction and blames the Western media for exaggerating Darfur's woes. (Reporting by Opheera McDoom)