KHARTOUM: Tanks, artillery and helicopters staged a show of force in the capital of Sudan's South Kordofan state on Friday, official media said, after unprecedented and deadly rebel shelling of the town.

Soldiers, police, internal security officers and Popular Defence Force militia members joined the parade in Kadugli, the state SUNA news agency reported, without saying how many people took part.

"Anyone who wants peace, we will talk with them, but anyone who wants war, we will fight him," SUNA quoted Ahmed Haroun, governor of the oil-producing state, as saying at the event.

Official media said seven women and children were killed in Monday's barrage by the ethnic and religious-minority Sudan People's Liberation Movement-North (SPLM-N).

The surprise attack coincided with a peace conference in Kadugli between Sudan's ruling National Congress Party and others about how to end the 18-month-old war which the United Nations says has displaced or severely affected hundreds of thousands of people.

"SPLM-North wanted to send a message saying 'We are here,' but this message came on the bodies of women and children," Haroun said.

The United Nations condemned Monday's attack, which it called indiscriminate and reprehensible. One shell landed in the UN Children's Fund (UNICEF) compound but failed to explode.

SPLM-N said it regretted any civilian casualties that may have been caused but said its artillery fire -- which continued on Tuesday and Wednesday -- was self-defence in the face of government shelling and aerial bombardment of rebel positions.

The rebel attack came after Sudan and South Sudan in late September signed deals on security and cooperation that they hailed as ending their countries' conflict.

The neighbours fought along their undemarcated frontier in March and April, sparking fears of wider war and leading to a UN Security Council resolution ordering a ceasefire and the settlement of unresolved issues, under African Union mediation.

Among the deals reached in Addis Ababa is agreement on a demilitarised border buffer zone designed to cut support for SPLM-N rebels in South Kordofan and Blue Nile states.

Khartoum accuses the government in Juba of backing those insurgents, and South Sudan in turn says Sudan has armed rebels in its territory.

SPLM-N rebels battled alongside insurgents from southern Sudan who waged a 22-year civil war which ended in a 2005 peace deal leading to South Sudan's independence last July.