President Donald Trump announced Monday the United States would add North Korea to its list of terrorism sponsors. The decision was reportedly under discussion for weeks and was confirmed by White House press secretary Sarah Huckabee Sanders.

North Korea joins three other nations on the U.S. “State Sponsors of Terrorism” list. Syria was added to the list in 1979. Iran was added in 1984, while Sudan was added in 1993. North Korea, meanwhile, was previously on the list but was removed by the State Department in 2008, according to Politico. The countries in question are penalized with four main categories of sanctions including restrictions on U.S. foreign assistance, a ban on defense exports and sales, certain controls over exports of items and other financial restrictions.

North Korea's addition to the list comes as largely a symbolic move as the nation is already subject to heavy sanctions by the United States and other international entities. 

Trump had not yet released any official details regarding the designation, but previous reports said the administration was debating putting North Korea back on the list in part due to the apparent assassination of Kim Jong Un's half-brother in February. Kim Jong Nam was killed at a Malaysian airport after two women appeared to attack him. An autopsy revealed he died of VX nerve poison, though North Korea denied the allegations and said he died of a heart attack.

"A regime who murders someone in a public airport using nerve agent and a despotic leader who murders his brother in that matter, I mean, that's clearly an act of terrorism that fits in with a range of other actions," National Security Adviser H.R. McMaster said in a briefing on the matter earlier in November.