Sudanese rebels swept through a major town in North Kordofan state, residents said on Saturday, widening an anti-government offensive in one of the insurgents' most audacious acts in years.
North Kordofan has been largely free from the rebel activity taking place in the Darfur region to its west, and South Kordofan to its south.
"This is part of our strategy to overthrow the regime and we want to weaken the troops on the road towards Khartoum," said Gibril Adam Bilal, spokesman for Darfur's Justice and Equality Movement (JEM) which is part of a rebel coalition.
"This is an attack deep in Sudanese territory."
Residents of Umm Rawaba, the second-largest town in North Kordofan, said rebels arrived Saturday morning on at least 20 vehicles for a brief occupation.
They fired their weapons into the air, causing panic, but met no initial resistance from security forces, townspeople said.
"We just saw some drones in the air," one resident said, adding the insurgents looted the market.
Other residents said the town's inhabitants cowered in their homes as rebels shot up government buildings before withdrawing.
JEM and other main rebel movements from Darfur are grouped in the Sudan Revolutionary Front (SRF) with insurgents from South Kordofan and Blue Nile states.
Sudan Armed Forces (SAF) spokesman Sawarmi Khaled Saad said coalition rebels crossed from South Kordofan into North Kordofan where they targeted Umm Rawaba town.
"They destroyed the communication tower and electricity station and looted civilian property and a fuel station," he said, quoted by the official SUNA news agency.
"SAF troops in the town responded," Saad said. "Fighting is still going on."
A resident, however, reported no combat in the town but heavy explosions in the surrounding area, where he had seen Antonov bombers and helicopters in the air.
"There are extensive air strikes in the Umm Rawaba area", Bilal said.
Rebel forces had pulled out of the town but remained in the surrounding area where they blocked a highway, he said.
The spokesman for the Sudan People's Liberation Movement-North (SPLM-N), which analysts say has controlled an area of South Kordofan just south of Umm Rawaba, said he had no information.
SPLM-N is also fighting in Blue Nile state.
Umm Rawaba, with a population of several thousand, is about 100 kilometres (60 miles) east of El Obeid, the capital of North Kordofan which produces gum arabica, an ingredient in soft drinks and other products. Sudan is the world's biggest producer of gum arabica.
Although JEM has occasionally operated just over the Darfur border in the western part of North Kordofan, this is their first strike into the east of the state.
In 2008 JEM pushed all the way to Khartoum's twin city Omdurman where government forces said the rebels were beaten.
The rebel attack in North Kordofan comes after President Omar al-Bashir on April 1 announced that all political prisoners would be freed as the government seeks a broad political dialogue, "including (with) those who are armed."
Rights groups last Monday said only 24 prisoners have been freed but at least 100 others, mostly from South Kordofan and Blue Nile, remain in custody.
The number of detentions in Darfur is not possible to verify, said Human Rights Watch and two other rights groups.
SRF early this year signed a pact with representatives of opposition political parties to replace Bashir's 24-year regime with a "democratic federal state... based on equality."
Khartoum this week held its first direct talks with the SPLM-N in almost two years. The peace talks took place in Ethiopia.