North Korea has test-fired several short-range missiles; a day after South Korea withdrew officials from the inter-Korean industrial zone.

South Korea displayed calmness over the missile launch.

Lee Dong-kwan is Presidential spokesman.

''We think it is just part of regular training, but we're closely monitoring the situation. I don't think North Korea would want a strain in inter-Korean relations.''

The spokesman said South Korean President Lee Myung-bak was briefed on the news of the launches, but didn't show a severe response.

South Korea's Yonhap News Agency reported that the North showed signs earlier this week that it was preparing to test short-range missiles as part of routine training.