Twenty-nine Chinese workers kidnapped in Sudan have been freed, 11 days after they were taken hostage by rebels in Southern Kordofan state.

The Red Cross flew the workers from the Kauda area in Southern Kordofan on Tuesday to Nairobi where they were handed over to Chinese embassy officials.

Rebels with the Sudanese People's Liberation Movement-North seized the workers in late January at a camp operated by a Chinese road construction company.

The Sudanese government has been engaged in fighting with the rebels in the oil-rich region, which is located along the border with newly independent South Sudan. The rebels have traditionally been aligned with the south.

China is a major investor in Sudan and had appealed to Khartoum to help secure the workers' release.

After their release Sudan issued a statement assuring China that Khartoum “seeks to protect Chinese investments and workers.”

During the January kidnapping, 17 Chinese workers managed to escape, while another one disappeared.

China's Xinhua news agency reported on Monday that Sudanese authorities handed over the body of the missing worker, who was killed following the attack.

China's growing economic involvement in Africa includes oil drilling and road projects in insecure areas often considered too dangerous to operate in by Western companies.

Sudanese officials say China has more than 100 companies and 10,000 personnel working in the country.

China is also the largest buyer of Sudanese oil and has tried to help the two Sudans settle a bitter dispute over oil revenue. The south took over the bulk of Sudanese oil production when it became independent in July but relies on northern pipelines for export.