Australia signed a security deal on Tuesday with the Pacific islands nation of Vanuatu, it said in a statement, amid concern over China's military ambitions for the strategically important region. Australian Foreign Minister Penny Wong is visiting Vanuatu with a bipartisan delegation, as Australia steps up its diplomacy throughout the Pacific islands after the Solomon Islands signed a security pact with Beijing in April. In May, China sought but failed to reach a wider security and trade pact with 10 out of 18 Pacific island nations. Australia and New Zealand have argued security and policing needs should be met within…