Trouble is brewing in the South China Sea. Beijing has just conducted a massive show of force, sending three naval fleets to participate in war games – televised in case anyone wasn't watching. This may not have been a direct response to US secretary of state Hillary Clinton, who made remarks about the South China Sea that angered Beijing. But they are a potent reminder of China's growing capacity – and willingness – to project strength regionally.

Speaking at a regional security gathering in Hanoi, Mrs Clinton said it was in Washington's “national interest” to see international settlement of disputes in the South China Sea, principally over the Spratly and Paracel island chains. These islands, and their surrounding waters, have long been claimed by China and Vietnam, with Malaysia, the Philippines, Indonesia, Taiwan and Brunei also staking claims.

Mrs Clinton was signalling that Washington is prepared to stand up for smaller south-east Asian nations, which feel increasingly bullied by Beijing. China has taken to chasing off Vietnamese fishing fleets and pressuring international oil companies to drop undersea development plans with neighbours. A recent opinion piece in the China Daily described the secretary of state's remarks as “a gambit aimed at containing China's rise”. The defence ministry reiterated China's “indisputable sovereignty” over the South China Sea and objected to US attempts to “internationalise” the issue.