President Donald Trump designated North Korea a state sponsor of terrorism on Monday, allowing the United States to impose additional sanctions and penalties against Pyongyang as it continues to pursue nuclear weapons programmes amid heightened nuclear tensions on the Korean peninsula.The Republican president, who has traded personal barbs and insults with North Korean leader Kim Jong Un, said the treasury department will announce the additional sanctions against the country on Tuesday.The designation came a week after Trump returned from a 12-day, five-nation trip to Asia in which he made containing North Korea’s nuclear ambitions a centrepiece of his discussions with world leaders.“Today, the United States is designating North Korea as a state sponsor of terrorism,” Trump told reporters at the White House. “Should have happened a long time ago, should have happened years ago.”Trump called it part of the US “maximum pressure campaign” against the North. North Korea will join Iran, Sudan and Syria on the list of state sponsors of terror.“In addition to threatening the world by nuclear devastation, North Korea has repeatedly supported acts of international terrorism including assassinations on foreign soil,” Trump said during a cabinet meeting.North Korea is pursuing nuclear weapons and missile programmes in defiance of UN Security Council sanctions and has made no secret of its plans to develop a missile capable of hitting the US mainland. It has fired two missiles over Japan.South Korea’s spy agency said on Monday North Korea may conduct additional missile tests this year to polish up its long-range missile technology and ramp up the threat against the US.Some experts, and US officials speaking privately, have argued that North Korea does not meet the criteria for the designation, which requires evidence that a state has “repeatedly provided support for acts of international terrorism”.Experts also say the move will be largely symbolic, as North Korea is already heavily sanctioned by the US.US officials involved in the internal deliberations have also said there was no debate over whether the slaying of North Korean leader Kim Jong Un’s estranged half-brother Kim Jong Nam in a Malaysian airport earlier this year was an act of terrorism.Lawyers said there had to be more than one incident, and there was disagreement over whether the treatment of American student Otto Warmbier, who died of injuries suffered in North Korean custody, constituted terrorism.The move returns North Korea to the ignominious list for the first time since 2008, when the country was removed in a bid to salvage a deal to halt its nuclear development. In the years since, the North has made advanced leaps in both its nuclear and missile programmes, proving the capacity to reach US territories with the devastating weapons earlier this year.