Sudanese rebels said on Monday they will release soon 29 Chinese workers held in the border state of South Kordofan where the army has been fighting insurgents for months.
Rebels from the SPLM-North had kidnapped the Chinese construction workers last month in oil-producing South Kordofan which borders newly-independent South Sudan.
The Chinese workers will be released soon and talks between the SPLM-North and the Chinese government continue, said rebel spokesman Arnu Ngutulu Lodi.
He said air strikes by the Sudanese army were obstructing the release, adding that the SPLM-North now awaited an agreement between Sudan and China to arrange the handover.
The Sudanese army could not be reached for comment.
Chinese Foreign Ministry spokesman Liu Weimin told reporters in Beijing that embassy diplomats had been in contact with the kidnapped workers by telephone.
At present, the health of those who have been kidnapped is good, they are in fine spirits, and work to rescue them is on-going. China is using various channels and taking all available actions to get rescue operations going, but I cannot give details for security reasons, Liu said.
The kidnapping, the third of Chinese citizens in Sudan since 2004, highlights the risks to China's expanding economic footprint in Africa, particularly in troublespots often shunned by Western companies.
Beijing is facing immense pressure to secure the safe return of the workers. State-owned newspapers have called for more protection for its overseas workers as the world's second-largest economy expands its investments around the globe.
The Sudanese army has been fighting SPLM-North rebels in South Kordofan since June. The violence spread to the northern Blue Nile state in September.
The fighting has forced 417,000 people to flee their homes, more than 80,000 of them to South Sudan, according to the United Nations.
Both states contain large groups who sided with the south in a decades-long civil war, and who say they continue to face persecution inside Sudan since South Sudan seceded in July.
The SPLM is now the ruling party in the independent south and denies supporting SPLM-North rebels across the border as charged by Khartoum.
SPLM-North is one of a number of rebel movements in underdeveloped border areas who say they are fighting to overthrow Sudanese President Omar Hassan al-Bashir and end what they see as the dominance of the Khartoum political elite.
(Reporting by Khalid Abdelaziz in Khartoum and Ben Blanchard in Beijing; Writing by Ulf Laessing)
(This story corrects to make clear in paragraph 6 China in contact with workers, not kidnappers)