Gunmen attacked a Chinese-run oil field in eastern Ethiopia Tuesday, killing 74 workers, said a spokesperson for the Chinese company.

"The attack happened this morning. Nine Chinese were killed, seven Chinese workers were kidnapped and 65 locals were killed," said Xu Shuang, the general manager of Zhongyuan Petroleum Exploration Bureau, based in Addis Ababa.

Rebel group the Ogaden National Liberation Front claimed responsibility for the raid, which took place in Abole, a town in the Somali state. The state includes the disputed Ogaden region.

The group sent a statement to the Associated Press saying it had launched "military operations against units of the Ethiopian armed forces guarding an oil exploration site" in the east of the country.

The rebel group, which is fighting to create an independent state for ethnic Somalis, vowed last year that any investment in the Ogaden area that also benefited the Ethiopian government "would not be tolerated."

Bereket Simon, an adviser to the Ethiopian prime minister, denounced the attack and vowed swift justice against the rebel group.

"This was a cold-blooded killing," Bereket said.

"The army is pursuing them. We will track them down dead or alive. We will make sure these people will be hunted and be brought to justice."

Bereket said the group is affiliated with the Eritrean government, which Ethiopia has accused of launching terrorist attacks, although Eritrea denies any terrorist action.

Chinese workers targeted

China has ramped up its industrial presence in Africa in recent years, seeking natural resources to feed its growing economy.

It has started projects in some politically unstable areas, a move that has left its workers vulnerable to attack.

Ethiopia is involved in fighting in neighbouring Somalia, assisting government forces against the rebel Islamic Courts Union, which briefly seized the Somali capital in June.

Ethiopia's presence in the country has met with hostility in some quarters, owing to long-standing tensions between the two nations. Disputes over the Ethiopian-controlled Ogaden region erupted into war in 1964 and again in 1977. Somalia lost control of the territory in the 1977 clash.

Chinese oil workers have also been targeted in Nigeria, where nine Chinese workers were kidnapped in January and another two were snatched in March.

Another five Chinese telecommunications workers were also kidnapped in January, but were released after a ransom was paid.

With files from the Associated Press