Kim Jong-un calls Donald Trump a ”mentally deranged U.S. dotard … a rogue and a gangster fond of playing with fire,” in an escalation of war of words between the two countries.

It’s the first time a North Korean leader has issued such a direct statement against an American president.

Trump responded by tweeting Kim is ”obviously a madman who doesn’t mind starving or killing his people.”

Kim says his country will consider the ”highest level of hard-line countermeasure in history,” but did not elaborate.

However, when asked what that might be, North Korea’s foreign minister said he thinks ”it could be the most powerful detonation of an H-bomb in the Pacific.”

Such a test would be considered a major provocation by Washington and its allies.

North Korea’s conducted six nuclear tests explosions the last 11 years.

The North was slapped with new, stiffer sanctions by the United Nations following its last and most powerful test September 3.