North Korea fired missiles into waters off its western coast Friday, as part of a military exercise, the South Korean president’s office and the Defense Ministry reported.

"The government regards North Korea's missile firing as merely a part of its ordinary military training," presidential spokesman Lee Dong-kwan told Yonhap, South Korea's news agency.

"The South Korean government will just continue to watch the missile-related situation carefully," he said. "We're convinced that North Korea doesn't want inter-Korean relations to deteriorate."

The test-firings came a day after North Korea expelled 11 South Korean diplomats from a joint industrial park situated on the border.

The diplomats were expelled after South Korean Unification Minister Kim Ha-joong had said last week that the industrial complex would be difficult to develop unless North Korea took steps in terms of denuclearization.

Yonhap news agency reported that North Korea had declared the minister’s comments as a reason for the diplomats’ departure.

U.S. and South Korea have urged North Korea to offer a complete declaration regarding its uranium enrichment program. This caused North Korea to react somewhat angrily.

"If the U.S. keeps insisting that what does not exist exists and delays the settlement of the nuclear issue, it would have a serious impact on the disablement of nuclear facilities,'' the Foreign Ministry was cited to say by the official Korea Central News Agency.

Respecting one accord of the six-party reached in February 2007, North Korea closed a nuclear reactor in Yongbyon, where it produced weapon-grade plutonium. After shutting down the reactor under the supervision of U.S. inspectors in November, the country still has to dismantle its nuclear program so that it can’t be used in the future.