Two U.S. defense Department said Monday that North Korea conducted another engine test of a ballistic missile.

According to officials, the latest engine test is third such test in the last few weeks with the use of similar technologies. One of the officials said an initial assessment indicates that the engine technology can be used in a possible Intercontinental ballistic missile.

Unclear whether the engine require any adjustment for use in ICBMs, if it can indeed be used in this way. The presence of Intercontinental ballistic missiles could allow North Korea to threaten the continental United States. ICBM technology is difficult to develop, because advanced missile project is a necessary step.

The US is also not sure whether North Korea's military to the miniaturization of a nuclear warhead, to be mounted on the missile such as an ICBM, although Pyongyang has said about this opportunity, and U.S. officials stated that they included this ability in their assumptions.

In a separate step, the US announced on Monday that the U.S. Marines first used the F-35B in South Korea as part of the exercise, which began on Friday. "This is the first time we used the F-35B to the Republic of Korea", - told reporters the representative of the Pentagon captain, U.S. Navy Jeff Davis. "Of course, we intend to defend the Republic of Korea and Japan against any aggression from North Korea, added Davis.
sections: Politics, World News, Accidents