State-of-the-art American stealth bombers have frequently been deployed in recent weeks for a military drill, raising speculations that they are part of Washington’s campaign to increase pressure on North Korea.

According to The Aviationist, a prominent military blog, a mock nighttime bombing exercise involving three B-2 Spirits were carried out in mid-October at Whiteman Air Force Base in Missouri.

It is the only aircraft in the U.S. Air Force that can drop the 14-ton bunker buster known as the GBU-57.

A video clip was also posted on the Web site, apparently showing the image of a B-2 Spirit dropping the massive bomb during the drill.

The Aviationist also quoted an unnamed American who claimed to have overheard radio communication among the pilots flying the military aircraft, mentioning “a command post possible DPRK leadership relocation site,” pointing to a simulated strike on the North.

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