As China demands the release of 29 of its citizens kidnapped in Sudan, another 25 Chinese nationals have been released a day after their abduction in Egypt.

The group was kidnapped Tuesday on their way to work at a cement factory in Egypt's Sinai region by Bedouin tribesmen. The kidnappers demanded the release of their tribesmen arrested several years ago for attacks in the Sinai.

An official with the Chinese embassy in Egypt says the workers were unharmed.

Meanwhile, Beijing has lodged a formal protest with Sudan over Saturday's capture of 29 workers when their camp was attacked by local rebels in South Kordofan state. The kidnappings have strained Sudan's relations with its powerful Asian ally, which is the largest buyer of oil from Sudan.

China's official Xinhua news agency says a Chinese team arrived in Sudan's capital Tuesday to help rescue the 29 workers. The report says a spokesman for the rebel Sudan People's Liberation Army-North told Xinhua the workers have been transported to a safe area and are in good health.

Reports from Sudan say that 18 Chinese workers fled to safety after the attack and headed toward Khartoum.

“We knew the Chinese embassy was trying to rescue us, so we were not scared. Our mind was on how we could cooperate with the embassy and the Sudanese army on their rescue operation. We've called our families and told them we are safe.”

South Kordofan borders newly independent South Sudan, which gained independence from Khartoum in July. Fighting broke out last year between Sudan and rebels in South Kordofan and in Blue Nile, another border state.

The SPLA-N has issued a statement calling on Beijing to remove its workers outside the war zone, to pressure Khartoum to open “safe corridors” for humanitarian operations, and to support its demand for an international investigation on alleged war crimes committed by the government against the Sudanese people.