KHARTOUM: Shells struck the capital of Sudan's war-torn South Kordofan state on Saturday, residents said, but there was no immediate word on any casualties.
"The last one just landed a few minutes ago," one resident of Kadugli told AFP.
Rebels of the Sudan People's Liberation Army-North (SPLA-N), fighting since 2011 in South Kordofan, have periodically shelled Kadugli since late last year, causing some fatalities.
Neither the SPLA-N nor Sudan's military could be immediately reached for comment.
"I heard about three mortars," a second resident told AFP, adding that two had hit the centre of town near a bus depot.
The other resident also said the town centre had been struck, but he spoke of six shells slamming into the area, forcing citizens to take cover.
Rebels, who have said their attacks on Kadugli target military facilities, last fired mortar rounds at the state capital in November, calling the strike retaliation for an air raid which killed two children.
The government has said that earlier rebel shelling of the town killed civilians.
In June, some rebel fire landed inside a United Nations peacekeeping base in Kadugli, killing one soldier.
Saturday's incident comes during an escalation of fighting in the region, after Defence Minister Abdelrahim Mohammed Hussein said in November that an operation had begun to crush Sudanese rebels.
The insurrection by the non-Arab SPLA-N is fuelled by complaints of political and economic neglect by the Arab-dominated Khartoum regime.
On Thursday, a senior UN official said the medical needs of 165,000 Sudanese children are being held "hostage" by the warring parties in South Kordofan and Blue Nile state, where SPLA-N is also fighting.
Those children "are not accessing basic health services, including vaccination against measles and polio", Martin Mogwanja, deputy executive director for operations at the UN children's fund (UNICEF), told reporters after a four-day visit to Sudan.
The youngsters are in rebel-held parts of the two states.
"It is not right for the different forces in conflict in those areas to hold these children as hostage, to hold their future as a hostage for the completion of a political process," Mogwanja said.
His appeal is the latest by the UN, which had brokered a November ceasefire between the two sides in order to carry out a polio vaccination campaign in the rebel-held zones as part of a nationwide effort.
But the warring parties would still not let aid workers in, and UN humanitarian operations director John Ging earlier blamed a "filibuster" by both the government and rebels.
Sudanese authorities have severely restricted access to the war zones for aid workers, journalists and foreign diplomats.
In April, the first peace talks in almost two years between the rebels and government stalled over the issue of humanitarian access.
The UN Security Council has stressed the need for a political solution to the conflict.
More than one million people have been severely affected or displaced by the fighting in South Kordofan and Blue Nile, the UN says.