North Korea looked to ratchet up already elevated tensions on the Korean peninsula still further Thursday, firing a pair of short-range missiles and announcing the liquidation of all remaining South Korean assets on its territory.

North Korea looked to ratchet up already elevated tensions on the Korean peninsula still further Thursday, firing a pair of short-range missiles and announcing the liquidation of all remaining South Korean assets on its territory.

The moves were a direct response to unilateral sanctions announced by South Korea on Tuesday to punish the North for its January nuclear test and last month's long-range rocket launch.

Military tensions have been on the rise ever since the January test -- the fourth nuclear device North Korea has detonated in defiance of UN resolutions.

The UN Security Council responded with tough, new sanctions, which Pyongyang condemned as a "gangster-like" provocation orchestrated by the United States.

The North also reacted furiously to the start earlier this week of large-scale South Korea-US military drills, threatening pre-emptive nuclear strikes against both Seoul and the US mainland.

The asset seizure announced on Thursday referred to two now-shuttered joint projects, the Mount Kumgang tourism resort and the Kaesong joint industrial complex.

"We will completely liquidate all assets of South Korean firms and related institutions left behind in our region," the Committee for the Peaceful Reunification of Korea said in statement carried by the North's official KCNA news agency.