After discussions with his opposite number in Tokyo, US Defense Secretary Chuck Hagel said on Sunday that the US would deploy two extra ballistic missile defense destroyers to Japan.

Hagel said the two ships would be sent in response to North Korea's "pattern of provocative and destabilizing actions," which he said were a violation of UN resolutions.

The announcement that the AEGIS ships would be sent follows the deployment of a second early warning radar to Japan, announced in October. Washington has also opted to increase its number of ground-based missile interceptors in Alaska.

"These steps will greatly enhance our ability to defend both Japan and the US homeland from North Korean ballistic missile threats," Hagel said following talks with Japanese Defense Minister Itunori Onodera.

The launch of ballistic missiles by North Korea is banned under resolutions by the UN Security Council adopted after multiple nuclear tests and rocket firings by Pyongyang.

The North was condemned by the UN for firing two medium range Rodong ballistic missiles on March 26 in a test over the Sea of Japan.

North Korean leader Kim Jong Un this week described the situation between the two Koreas, which have technically remained in a state of war since the 1950s as "very grave." He warned that Pyongyang would "thoroughly crush" what was described as a "US-orchestrated policy of hostility."

The North last week threatened a "new form" of nuclear test without specifying what it was. Earlier in the week both North and South Korean forces fired shots across a disputed maritime border.

rc/crh (AFP, AP)