Blue Nile: Sudan declares state of emergency
Sudan has declared a state of emergency in Blue Nile after fighting broke out in the state, on South Sudan's border.
State media said President al-Bashir had also appointed a military governor.
The party of elected Governor Malik Agar earlier said soldiers had attacked his official residence. The army blamed the fighting on the ex-rebel commander.
Blue Nile is the third border area to see fighting since South Sudan gained independence in July. In South Kordofan some 200,000 have fled their homes.
The government has denied charges its forces have carried out ethnic cleansing in the area against groups seen as being pro-south.
On Tuesday, Sudan's government lodged a complaint with the UN Security Council, accusing South Sudan governing party of backing rebels in South Kordofan, which the Sudan People's Liberation Movement (SPLM) denies.
There has also been fighting in Abyei, which is claimed by both sides.
The BBC's James Copnall in Juba says this is the first major outbreak of fighting in Blue Nile since the north-south conflict ended in 2005.
But he says the region was always a high risk state because it borders South Sudan and is split between supporters of President Omar al-Bashir's government and the SPLM.
Blue Nile Governor Malik Agar heads the SPLM-North party and is an ex-commander of the rebels who now govern South Sudan.
'Tanks and militia'
Sudan said Mr Agar's forces launched attacks on police stations and government buildings in the state capital, Damazin.
"The Sudanese Armed Forces responded to this attack and has now driven the rebels away. The government now controls Damazin and the area around it," government spokesperson Rabbie Abdelatti told the BBC.
A local resident said government tanks were patrolling the city and forces loyal to Mr Agar had withdrawn from the city.
SUNA news agency later reported: "President Omar al-Bashir declared a state of emergency in Blue Nile state and named a military commander in the Damazin area as military governor of the state."
Many residents have fled Damazin because they fear the violence could escalate, the resident said.
He and a UN source told the BBC fighting flared up on Thursday night and shooting could still be heard in Damazin on Friday.
The SPLM-North, which says it has split from the south's ruling party, says the army moved into strategic positions of Damazin with 12 tanks and 40 other armoured vehicles backed up by militia fighters.
It accused the government of declaring a surprise ceasefire in South Kordofan last week to prepare the ground for an attack in Blue Nile.
The SPLM led the decades-long struggle which culminated in independence for South Sudan.
When a peace deal was signed in 2005 to pave the way for the South's independence, the SPLM and Khartoum agreed Blue Nile and South Kordofan would have "popular consultations" about their future.
But these did not take place properly, leading to an increase in tensions and now clashes, our reporter says.
Mr Agar recently warned Khartoum of the dangers of taking on rebels in South Kordofan, Blue Nile and Darfur because they were likely to co-ordinate their efforts.
Opposition groups in the three areas accuse Khartoum of ethnic cleansing and failing to give them a fair share of the national wealth.
The International Criminal Court (ICC) has issued arrest warrants for Mr Bashir and the South Kordofan governor over the conflict in Darfur, accusing them of genocide and war crimes.
Mr Bashir denies the allegation and says the ICC is controlled by Western powers hostile to Sudan.
Last month, a UN report said both government and rebel forces may have committed war crimes in South Kordofan, but it said the army's actions were "especially egregious" - referring to summary executions, aerial bombardments and the shelling of neighbourhoods.
When South Sudan split from the north on 9 July, the new country's leader, Salva Kiir, said he would work with Mr Bashir to ensure the rights of former southern rebels in the north were respected.