A Sudanese rebel alliance on Monday declared North Kordofan state a target of its widening anti-government offensive, as parliament met to discuss the attacks.
Except for occasional rebel forays over the border from the conflict-plagued Darfur region, North Kordofan had been largely free from insurgency.
But on Saturday a rebel coalition struck a major North Kordofan town which residents said had been left unguarded and was hit during coordinated attacks in the insurgents' most audacious act in years.
"North Kordofan state has all become our target," Arnu Ngutulu Lodi, spokesman for the Sudan People's Liberation Movement-North (SPLM-N), told AFP.
SPLM-N, which has been fighting for two years in South Kordofan state, belongs to the Sudan Revolutionary Front (SRF) alliance which includes major insurgent groups from Darfur.
SRF said it attacked Umm Rawaba, the second-largest town in North Kordofan, and several other areas in North and South Kordofan as part of its strategy to reach the capital Khartoum and overthrow the 24-year regime of President Omar al-Bashir.
Lodi claimed that rebels on Sunday shelled the airport area of Kadugli, the state capital of South Kordofan, for the second time in two days.
He warned civil aviation to avoid the area, as well as the airspace in North Kordofan.