North Korea launched what appeared to be a second intermediate-range Musudan missile on Wednesday, June 22 that flew about 400 km (250 miles), in what appeared to be its most effective test yet, hours after another launch failed, South Korea's military said, according to Reuters.

It was not immediately clear if the second Musudan launch, about two hours after the first, was considered a success or failure, or how the flight ended. However, the distance it covered was theoretically more than halfway towards the southwest coast of Japan's main Honshu island.

The first missile was launched from the east coast city of Wonsan, a South Korean official said, the same area where previous tests of intermediate-range missiles were conducted, possibly using mobile launchers.

Yonhap, quoting a government official, said it disintegrated mid-air after a flight of about 150 km (95 miles).

The launches were in continued defiance of international warnings and a series of U.N. Security Council resolutions that ban the North from using ballistic missile technology, which Pyongyang rejects as an infringement of its sovereignty.

Wednesday's first launch would have been the fifth straight unsuccessful attempt in the past two months to launch a missile that is designed to fly more than 3,000 km (1,800 miles) and could theoretically reach any part of Japan and the U.S. territory of Guam.

However, Jeffrey Lewis of the California-based Middlebury Institute of International Studies, said failures were a normal part of testing and that North Korea would fix the problems with the Musudan sooner or later.

"If North Korea continues testing, eventually its missileers will use the same technology in a missile that can threaten the United States," Lewis told Reuters.