An Australian frigate has joined three U.S. warships in the South China Sea near an area where a Chinese vessel is suspected to be exploring for oil, near waters also claimed by Vietnam and Malaysia, officials said on April 22. The warships arrived this week close to where the Chinese government survey ship Haiyang Dizhi 8 has been operating, which is in turn near where a vessel operated by Malaysia’s Petronas state oil company is conducting exploratory drilling, regional security sources have said. The United States has accused China of pushing its presence in the South China Sea while other...