China on Friday accused the US of trying to "flaunt military force" to harm its sovereignty in name of freedom of navigation after two American bombers flew over the disputed South China Sea, disregarding Beijing's claims over the area.
Two US B-1B Lancer bombers flew over disputed waters in the East and South China Seas on Thursday night, conducting a joint military operation with Japanese fighter jets.
The bombers were joined by two Japanese F-15 fighters and carried out a cooperative mission over an area claimed by both Japan and China, US defence officials said on Friday.
This marked the first time US B-1 bombers from the Pacific Command have carried out an operation of this kind with Japanese fighters at night, according to a statement from US Pacific Air Forces.
''Flying and training at night with our allies in a safe, effective manner is an important capability shared between the US and Japan,'' said Major Ryan Simpson, Pacific Air Forces chief of bomber operations.
''This is a clear demonstration of our ability to conduct seamless operations with all of our allies,'' he added.
The bombers from Guam airbase flew over South China Sea as part of operations intended to demonstrate the US commitment to freedom of navigation, the US Air Force said in a statement.
Asked about the flight by the US bombers, Chinese Foreign Ministry spokesman Geng Shuang told media in Beijing that there was no problem with freedom of navigation or overflight for the East and South China Seas. "But China resolutely opposes individual countries using the banner of freedom of navigation and overflight to flaunt military force and harm China's sovereignty and security."
In a statement, the Defence Ministry said China always maintained its vigilance and "effectively monitors relevant countries' military activities next to China. The Chinese military will resolutely safeguard national sovereignty and security as well as regional peace and stability."
China claims sovereignty over all of South China Sea. Vietnam, Malaysia, the Philippines, Brunei and Taiwan have counter claims.
China is engaged in hotly contested territorial disputes in both the South China Sea and the East China Sea. Beijing has built up and militarised many of the islands and reefs it controls in the region.
Since Donald Trump took over the Presidency, the US has dispatched two warships close to the artificial islands built by China to assert freedom of navigation.
The US flights over the South China Sea came as Trump is due to meet his Chinese counterpart Xi Jinping on the sidelines of the G-20 summit in Hamburg to discuss among others the latest ICBM test by North Korea, which could reach US state of Alaska.
Trump has expressed unhappiness over China not doing enough to contain its ally North Korea.