A Chinese research vessel flanked by coast guard and nearly a dozen boats on Wednesday entered a gas block operated by Russian and Vietnamese state firms, two monitoring groups said, another potential flashpoint in the South China Sea.
It follows a pattern of assertive moves of late by Beijing in its neighbours' exclusive economic zones (EEZ), as it presses its claim to sovereignty over almost the entire South China Sea, testing the United States and its allies at a time of heightened regional tension.
