North Korea showing ‘unprecedented levels’ of submarine activity: report

North Korea has been showing “highly unusual and unprecedented levels” of submarine activity in the days following the country’s latest test of an intercontinental ballistic missile (ICBM), according to a CNN report.

Citing an unnamed U.S. defence official, CNN reported Monday the U.S. military also detected the third submarine “ejection test” in the month of July, and the fourth of the year.

The ejection test was carried out on land at Sinpo Naval Shipyard on Sunday, the U.S. defense official told CNN.

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These types of submarine tests are usually done to examine a missile’s ability to “cold launch” out of an ejection shoot by high-pressured steam. Once the missile is propelled out of the launcher and into the air, the missile’s engine then ignites before taking flight.

According to CNN, two defence officials said that a North Korean Romeo-class submarine participated in “unusual deployment activity” earlier this month that appeared to be not part of a training exercise. The news outlet reported the sub was patrolling the waters off the coast of Japan, some 100 kilometres in international waters.

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Citing a defence official, this activity caused U.S. and South Korean troops to slightly raise the alert level.

CNN’s report comes just days after North Korea said it had conducted another successful test of an ICBM that it claimed proved its ability to strike America’s mainland.

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Citing Korean Central News Agency, the Associated Press reported North Korea leader Kim Jong Un supervised the latest test and expressed “great satisfaction” as a result of the successful launch.

Officials said Friday’s ICBM test lasted about 45 minutes and the missile reached an altitude of about 3,700 kilometres before splashing down in the Sea of Japan.

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Experts believe Friday’s missile test shows that North Korea theoretically has the ability to reach major U.S. cities.

The Union of Concerned Scientists reported shortly after Friday’s test, that based on the preliminary numbers of flight time and distance travelled, if the rocket was launched at a “standard trajectory” this missile would have a reach of just over 10,000 kilometres.

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On Monday, U.S. President Donald Trump vowed to deal with North Korea’s weapons program.

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“We will handle North Korea,” Trump told reporters. “We’re going to be able to handle them. It will be handled. We handle everything.”

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–with a file from Reuters