DANANG (AFP) - Former enemies Vietnam and the United States began a joint naval drill on Friday, despite Chinese objections after weeks of escalating tension in the disputed South China Sea. US officials described the week-long exercises off Vietnam's central coast as "non-combatant events", focused on areas such as navigation and maintenance, in a statement from the consulate general in Ho Chi Minh City. But China's top military officer General Chen Bingde said Monday that the timing of US naval exercises in the area was "inappropriate", after talks with his American counterpart Admiral Mike Mullen aimed at cooling the tensions.