By Phil Stewart
TOKYO, April 6 (Reuters) - The United States will deploy two additional destroyers equipped with missile defense systems to Japan by 2017, in a move Defense Secretary Chuck Hagel said on Sunday was a response in part to North Korean missile launches that have alarmed the region.
Tensions have been building between North Korea and its neighbours since Pyongyang - in an apparent show of defiance - fired two Rodong missiles on March 26, just as the leaders of Japan, South Korea and the United States were sitting down to discuss containing the North Korean nuclear threat.
"In response to Pyongyang's pattern of provocative and destabilizing actions ... I can announce today that the United States is planning to forward-deploy two additional AEGIS ballistic missile defense ships to Japan," Hagel said at a news conference at Japan's defence ministry.
The move will bring America's Japan-based fleet of ballistic missile defense capable ships to seven.
Pyongyang's firing of mid-range missiles capable of hitting Japan followed a series of short-range rocket launches over the past two months. The Rodong ballistic missiles fell into the sea after flying 650 km (400 miles), short of a maximum range thought to be some 1,300 km, Japan said.
Since then, North Korea has fired artillery rounds into South Korean waters, prompting the South to fire back; South Korea has test-fired a new ballistic missile with a range of 500 km; and Pyongyang has threatened an unspecified "new form" of nuclear test.
"This move to significantly bolster our naval presence is another action that strengthens our alliance and increases deterrence against North Korean aggression," Hagel said.
Hagel said that the U.S. deployment of additional destroyers followed his decision last year to position a second X-band missile defense radar in Japan. That radar is expected to become operational this year.
It also follows his decision to increase ground-base missile defenses in Alaska.
"These steps will greatly enhance our ability to defend both Japan and the U.S. homeland from North Korean ballistic missile threats," Hagel said. (Additional reporting by Nobuhiro Kubo; Editing by Michael Urquhart)