US President Donald Trump slammed North Korean leader Kim Jong-un for "acting very, very badly", following Pyongyangs missile activities, a media report said.North Korea claimed it tested a new high-thrust rocket engine on Saturday, the latest in a string of missile tests over the past few months, The Hill magazine said in the report."He's acting very very badly," the President on Sunday said of Kim Jong-un, according to the White House.Trump, who travelled to his Mar-a-Lago resort, Florida, said he discussed North Korea's missile launches during meetings over the weekend.Secretary of State Rex Tillerson also denounced North Korea's missile launches last week, indicating that the Trump administration is open to taking pre-emptive action if Pyongyang continues to "elevate the threat of their weapons programme".