China ends drilling in waters claimed by Vietnam

China on Wednesday moved an oil rig that it had deployed in a section of the South China Sea, triggering a dispute with Vietnam.

Beijing deployed the massive rig in early May close to the Paracel Islands, causing a furious reaction in Hanoi and the most serious uptick in tensions in the waters in years.

Hanoi demanded that Beijing withdraw the rig, and sent ships to the region to try and disrupt the operations. The Chinese move triggered protests in Vietnam and deadly anti-Chinese riots.

Beijing insisted it had done nothing wrong because the waters belonged to it, but the deployment of the rig was widely seen as part of a strategy by China of gradually staking out its claims in the South China Sea, all or part of which is also claimed by Vietnam, the Philippines, Taiwan, Malaysia and Brunei.

China National Petroleum Corp. (CNPC), the dominant oil and gas producer in China, said in a statement that the rig "smoothly completed" drilling on Tuesday and found signs of oil and gas. The next step would be to analyze the geological data and evaluate the layers of oil and gas, it said.

CNPC's preliminary analysis showed "the area has the basic conditions and potential for oil exploration, but extraction testing cannot begin before a comprehensive assessment of the data," the Xinhua news agency quoted Wang Zhen, deputy director of the CNPC Policy Research Office, as saying.

China had previously said the rig was scheduled to explore the waters around the Paracels until mid-August. It was not clear why it had finished one month ahead of schedule, although Xinhua said July was the beginning of the typhoon season.

China's popular Twitter-like microblogging service Weibo lit up with criticism of the move, according to Reuters. Many people said the government had bowed to the United States, underscoring the domestic pressure Beijing faces to be tough in its territorial disputes.

Ha Le, deputy director of Vietnam's fisheries resources surveillance department, said China began removing the rig and escorting vessels Tuesday night, and by 8 a.m. Wednesday it was 40 nautical miles northwest of its original location and continuing to move toward Hainan island.

Le said 30 vessels from Vietnam's coast guard and fisheries patrol forces that were sent to try to compel the Chinese oil rig to leave will return to port to avoid the incoming Typhoon Rammasun.

The deployment of the rig was seen as a highly provocative move by China, and the United States criticized the placement "as part of a broader pattern of Chinese behavior to advance its claims over disputed territory in a manner that undermines peace and stability in the region."

As a result of the rig placement, Vietnamese Prime Minister Nguyen Tan Dung has said the country was preparing to file a legal challenge to China's claims in an international tribunal, something that risks angering China. It remains to be seen whether Vietnam will go ahead with that now the rig has been withdrawn.

Al Jazeera and wire services