WASHINGTON. The US is ready to defend itself against anything North Korea might launch, Defence Secretary Chuck Hagel said, as its ally South Korea confirmed its ability to intercept the North’s missiles.At a Pentagon briefing on Wednesday, Hagel told reporters that the US "is fully prepared to deal with any contingency, any action that North Korea may take or any provocation that they may instigate,” Hagel added.He said that the North was "skating close to a very dangerous line” with its bellicose rhetoric and was adding to a "combustible” situation."What the US would call crossing a ‘dangerous line’ would be launching a missile without any kind of pre-warning to shipping and to air traffic that it was about to do so,” said Al Jazeera’s Harry Fawcett, reporting from Seoul. "In the past, North Korea has, in advance of its rocket launches, given a warning and an idea of the trajectory that its missiles would take."This time all indications are that [North Korea is] preparing a missile launch on the east coast [without warning].”General Martin Dempsey, chairman of the Joint Chiefs of Staff, noted that in the absence of statements to the contrary then the confrontational statements have to be taken at face value."They have conducted two nuclear tests, they have conducted several successful ballistic missile launches and in the absence of concrete evidence to the contrary, we have to assume the worse case,” said Dempsey.On Thursday, a South Korean defence ministry official said that Seoul has deployed three naval destroyers, an early warning surveillance aircraft and a land-based radar system, as the South braced for what the country’s foreign minister said could be a test-fire of a medium-range missile.