- Vietnam says China has moved oil rig to disputed waters
- Similar move in 2014 triggered violent protests in Vietnam
- China says waters are controlled by China
The country's foreign ministry spokesman Le Hai Binh said Tuesday that China had moved its Haiyang Shiyou 981 oil rig to an area outside the Gulf of Tonkin on January 16.
"Vietnam requests China not to conduct drilling activities and to withdraw the HYSY 981 oil rig from this area," a statement from Vietnam's Ministry of Foreign Affairs said.
The oil rig was moved to "an overlapping area" between the two continental shelves of Central Vietnam and China's Hainan Island that had not been demarcated, it said.
The spokesman added that a ministry representative had met with an official from the Chinese embassy in Hanoi on Monday.
China: We control waters
In response, China's foreign ministry spokesperson Hong Lei said that the drilling platform was operating in "Chinese controlled waters that are completely undisputed."
"We hope the Vietnamese side can view this calmly, meet China half way and jointly work hard to appropriately handle relevant maritime issues," he told reporters Wednesday.
In 2014, Beijing was forced to evacuate thousands of Chinese nationals from Vietnam after violent protests erupted
over Chinese exploratory drilling in disputed waters near the Paracel Islands.
Rich in oil and gas reserves, the South China Sea is home to a messy territorial dispute that pits multiple countries against each other.
Tensions have risen over the past two years as China has embarked on a massive land reclamation program -- turning sandbars into islands equipped with airfields, ports and lighthouses.
Delegates from Vietnam's ruling Communist Party begin a key meeting Wednesday to pick new leaders and chart the country's economic and foreign policy for the next five years.