China urged Sudan on Tuesday to seek urgently the release of 29 Chinese workers held by rebels in the border state of South Kordofan, declaring that it was shocked by their abduction.

The Chinese Vice Foreign Minister Xie Hangsheng summoned a senior diplomat at Sudan's embassy in Beijing to deliver the message, the official Xinhua news agency said in a bulletin.

In a separate incident, Bedouin tribesmen in Egypt's Sinai region kidnapped 25 mostly Chinese cement factory workers on Tuesday, demanding that authorities free fellow Bedouin from prison, sources from the tribe said.

China's message to Sudan underscored the pressure that China faces to secure the safe return of the abducted construction workers, as did its announcement earlier on Tuesday that it had sent officials from the Foreign Ministry and other agencies to Sudan the previous day to assist in rescue work.

The workers' plight has attracted widespread attention in China and any deaths could become a more serious headache for the government, which Chinese citizens assume can wield its influence to protect nationals abroad.

The abduction is the latest incident dramatising China's difficulties with companies and workers venturing to dangerous places generally shunned by Western companies.

The Chinese government attaches much importance to protecting citizens abroad and feels shocked about this abduction incident, said Xie, the Chinese Vice Foreign Minister, according to the ministry's website (www.mfa.gov.cn).

The Chinese government urges Sudan to act out of regard for our two countries' friendly cooperation, and to keep using a variety of channels to intensify rescue efforts, doing everything possible to ensure the safety of the Chinese nationals and striving by every means to create the conditions for their safe release as soon as is possible.

The rebel Sudan People's Liberation Movement-North (SPLM-N) said it took the 29 workers on Saturday for their own safety after a battle with the Sudanese army.

Since June, the Sudanese army has been fighting the SPLM-N in South Kordofan, which is in Sudan bordering the newly independent country of South Sudan.

There was initially hope that some of workers had been released, after Sudan's state news agency said the military freed 14 of them.

But on Monday, Chinese and Sudanese officials denied the report. The Chinese Foreign Ministry said 29 of the workers remained in rebel hands while another 17 had reached safety and one was missing.

PRESSURE ON SUDAN'S GOVERNMENT

China's ambassador to Sudan, Luo Xiaoguang, also upped the public pressure on the Sudanese government, according to the Xinhua news agency, urging authorities to find the Chinese nationals quickly.

The evacuation of tens of thousands of Chinese workers trapped in Libya when fighting broke out there early last year also became a major news event in China. Chinese workers and engineers in Sudan were also abducted in 2004 and 2008.

The kidnapping of the workers in Egypt's Sinai region, who were on their way to a cement plant, will exacerbate worry in China about overseas workers.

The Sinai workers were being held in a tent near a road that the Bedouin had blocked for the past three days to press their demand, the tribal sources said.

China's Xinhua news agency said the country's embassy in Cairo was asking the Egyptian government to handle the incident immediately.

China has interests in oil and infrastructure throughout the region, including both Sudan and South Sudan. But those two newly divided countries at odds over issues including oil revenues. Each accuses the other of supporting insurgencies.

China has more than 100 companies and 10,000 personnel working in both north and south Sudan, China's then-ambassador to Khartoum, Li Chengwen, said last year.

The workers abducted in Sudan are employees of the Sinohydro Corp Ltd, which said they were building a $63.2 million (40.0 million pounds) road project funded by the Export-Import Bank of China, according to the People's Daily website (www.people.com.cn).

South Kordofan is the main oil-producing state in Sudan. The SPLM is the ruling party in newly independent South Sudan, which broke off from its northern neighbour. South Sudan denies supporting SPLM-North rebels across the border.

SPLM-North is one of a number of rebel movements in underdeveloped border areas that 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.

(Additional reporting by staff in Egypt; Editing by Ken Wills and Robert Birsel)