Fear and anger on Sunday followed a Sudanese rebel strike on a major town residents said had been left unguarded and was hit during coordinated attacks in the insurgents' most audacious act in years.

In Umm Rawaba, a previously peaceful community of thousands which bore the brunt of Saturday's attack, residents said about 300 youths stoned a convoy carrying North Kordofan state governor Murghani Hussein Zaki-Adeen, and federal Electricity Minister Osama Abdullah Mohammed.

"Where were you yesterday?" witnesses said protesters shouted after the governor visited the homes of people who died in the unrest.

Youths then set fire to local government buildings, said witnesses.

Residents complained that the town, the second largest in North Kordofan, had been left undefended when insurgents briefly occupied it on Saturday.

The death toll was unclear but included some policemen, according to residents and officials.

Rebels said eight of their number died during the operation, four in battle and four in accidents.

North Kordofan has been largely free from the insurgencies in the Darfur region to its west, and South Kordofan to its south.

But a rebel coalition, the Sudan Revolutionary Front (SRF), said it attacked Umm Rawaba and several other areas as part of its strategy to reach the capital Khartoum and overthrow the 24-year regime of President Omar al-Bashir.

Umm Rawaba is about 100 kilometres (60 miles) east of the state capital El Obeid, which is home to an air force base and on Sunday was tense with armoured vehicles deployed and soldiers in the streets, a resident said.

SRF chief of staff Abdulaziz Al-Hilu on Saturday said rebels seized government garrisons at Abu Kershola and Um Ktera before "chasing" the army to Umm Rawaba, Allah Kareem and to the edge of North Kordofan's El Rahad town.

Abu Kershola and Um Ktera were still in rebel hands on Sunday, while two additional South Kordofan garrisons nearby had also been captured by SRF, said Arnu Ngutulu Lodi, spokesman for the Sudan People's Liberation Movement-North (SPLM-N).

Residents of Abu Kershola, a village about 65 kilometres south of El Rahad, said they were living rough after fleeing.

"We are staying under trees and we are using camels to bring water from far away. Some families have nothing to eat. We are calling for the government to deliver aid," said one of the displaced, Ahmed Ibrahim.

"There are just a few trees to shelter the young children and old people," said another man, Hamid Ahmed Mohammed, who fled the village early on Saturday.

"There is no food and we brought our water in by donkey," he said.

They could not say how many people were displaced because they were scattered over a wide area.

Calm had returned to Umm Rawaba town on Sunday but there was no electricity or water following the rebel attacks, townspeople said.

"People are still fearful," one resident said.

Hafez Mohammed Hamoud, North Kordofan's Minister of Finance, said Allah Kareem and the area outside El Rahad were also "under control completely."

Sudan's army spokesman could not be reached but on Saturday, quoted by SUNA, he said the rebels had been "defeated" and had scattered in small groups.

The SRF consists of SPLM-N and Darfur's main rebel groups the Sudan Liberation Army and Justice and Equality Movement (JEM).

In 2008 JEM pushed all the way to Khartoum's twin city of Omdurman where government forces said they were beaten.