BEIJING: China on Thursday defended the deployment of anti-ship cruise missiles and surface-to-air missile systems in the disputed South China Sea , saying it has "indisputable sovereignty" over the area.China is engaged in hotly contested territorial disputes in both the South China Sea and the East China Sea . China claims almost all of South China Sea. Vietnam, Philippines, Malaysia, Brunei and Taiwan have counter claims."China has indisputable sovereignty over the Nansha (known as Spartly) islands and its affiliated islands," foreign ministry spokesperson Hua Chunying told a media briefing here when asked about the reported of deployment of the missiles.Vietnam and Taiwan have rival claims over Spratly islands."China's activities in the South China Sea is to uphold our sovereignty and territorial integrity. It is our right," she said.Virtually confirming the deployment of the missiles, Hua said, "relevant deployment is not directed against any country. The relevant parties should not be concerned about this and should view this in an objective way."The US media reports earlier said China has installed anti-ship cruise missiles and surface-to-air missile systems on three of its outposts in the South China Sea.The reports said the missiles were moved to Fiery Cross Reef, Subi Reef and Mischief Reef within the past 30 days.In April, the Chinese military held its largest ever maritime drill in the disputed South China Sea during which it displayed for the first time the country's aircraft carrier strike group and the most advance weaponry of the People's Liberation Army ( PLA ).The drill was held amid frequent forays made by US naval and aircraft into the South China Sea to assert the freedom of navigation especially around the artificial islands built by China, where it has also established garrisons.The strategic South China Sea is rich in energy reserves, fishery resources and is a busy shipping route.