South Korea's defense minister warned Wednesday that North Korea could conduct a nuclear or long-range missile test, following a series of short-range missile launches Seoul slammed as provocative.
Defense Minister Kim Kwan-jin told a parliamentary committee that South Korean and United States forces are on alert, and he "could not exclude the possibility" of long-range missile or nuclear tests.
Since last Thursday, North Korea has fired at least 11 short-range missiles and other projectiles into the ocean off its east coast. The launches are seen as a response to ongoing joint U.S.-South Korean military drills.
A spokesman for the North Korean military on Wednesday called the tests routine, legitimate, and for the purpose of self-defense. Speaking to the official Korean Central News Agency, he denied the launches were raising tensions.
The spokesman instead blamed Seoul and Washington for damaging regional stability and warned that if they go too far, the rockets will no longer be used for self-defense.
The statement was also read on North Korean state television.
"All our revolutionary strength's military actions, without exception, were conducted as defensive actions for justice in order to protect our air, sea and land of the country and people's safety as well as the peace of the region."
North Korea has in the past struck South Korean targets during Seoul's military drills. Following a South Korean military exercise in 2010, North Korea shelled a South Korean island, killing four people.
Meanwhile, Seoul says one of the short-range rockets launched Tuesday by North Korea crossed the trajectory of a Chinese airliner, heading from Japan to China with 200 people on board.
China, which is North Korea's only major ally, has made its usual call for calm and restraint following the launches.
Washington has condemned the missile tests as a violation of United Nations Security Council resolutions banning North Korean ballistic missile activity.
North Korea conducted a long-range missile test in December 2012. It conducted its third nuclear test two months later.