Vietnam requested Tuesday that China withdraw military equipment from the South China Sea, following media reports this month that China had installed missiles there.
"Vietnam requests that China, as a large country, shows its responsibility in maintaining peace and stability in the East Sea," Vietnamese Foreign Ministry spokeswoman Le Thi Thu Hang said in a statement, referring to the South China Sea.
The statement came after U.S. news network CNBC reported this month that China had installed anti-ship cruise missiles and surface-to-air missile systems on three of its outposts in the South China Sea, citing sources with direct knowledge of U.S. intelligence reports.
Vietnam and China have been embroiled in maritime disputes in parts of the South China Sea, where China claims 90 percent of the potentially energy-rich maritime territory.
"Vietnam is extremely concerned about the information [as reported] and reaffirms that all militarization activities, including the installation of missiles on the Spratly islands, is a serious violation of Vietnam's sovereignty," Hang said in the statement posted on the ministry's website Tuesday.
The installations, if confirmed, would mark the first Chinese missile deployments in the South China Sea, where other Asian countries including Taiwan, the Philippines and Brunei, have rival claims.
China has made no mention of any missile deployments but says its military facilities in the Spratlys are purely defensive, and that it can do what it likes on its own territory.