The government is trying to verify Japanese media reports that North Korea is preparing to test-fire a long-range Taepodong II ballistic missile.

A senior Defense Ministry official said Friday that the reported signs are likely untrustworthy but that the ministry is closely monitoring the situation and taking necessary measures along with other agencies.

He declined to elaborate on the measures, citing the sensitivity of the issue.

A source familiar with North Korea in Seoul said the ministry and the Pentagon detected early this week unusual signs around the North's missile base in North Hamkyong Province and are checking them.

The source said the two sides are trying to determine whether Pyongyang is preparing for a missile launch or is simply staging a protest against U.S. pressure on the North to scrap its nuclear program.