President Donald Trump announced Monday that he is putting North Korea back on the U.S. government’s list of state sponsors of terrorism and plans to slap a “very large” sanction on Pyongyang.

Trump has mulling whether to put North Korea back on the list  for weeks. He and his senior aides decided to hold off until after his 12-day Asia swing, which ended last Wednesday. It was removed under a 2008 deal struck by the George W. Bush administration.

Designating North Korea a state sponsor of terrorism will allow Trump to impose further sanctions on the North over its nuclear arms and long-range missile programs.

To that end, the Treasury Department on Tuesday will announce “a very large” new sanction on the North that will be the “biggest” the United States has imposed on the Kim government, he said.

That sanction, which he cast as the “highest level ever” by the United States on North Korea, will come with the formal designation that the North is back on the list.

“It should have happened years ago,” the commander in chief said, referring to the Kim government as “a murderous regime.”

North Korea “must end its unlawful ballistic missile development and cease its support for all terrorism activities” and has yet to to either, Trump said. He also accused the Kim government of “assassinations on foreign soil.” North Korean leader Kim Jong-un’s estranged half brother was killed in earlier this year at an airport in Malaysia.

Countries that are added to the list are deemed by the U.S. State Department to “have repeatedly provided support for acts of international terrorism,” according to a State Department fact sheet.

The timing of slapping the state sponsor of terrorism label back on North Korea is merely due to the recent completion of an internal review process, Secretary of State Rex Tillerson said during the White House press briefing.

Trump administration officials are encouraged the North Korean leader Kim Jong-un and his government have been “quiet” recently, Tillerson said, adding U.S. officials hope that continues. The administration is confident “a number of revenue streams are down” for the Kim government due to existing sanctions, he said.

The new U.S. sanction coming Tuesday is aimed at influencing “third parties” against doing business with North Korea, Tillerson said.

“It is very symbolic … because it just points out again … how brutal this regime is,” Tillerson said of the state terrorism sponsor tag for North Korea. “The practical effects may be limited.”

He said U.S. officials have concluded there are fuel shortages inside North Korea, and he signaled the Trump administration wants China to do more to further squeeze the North by further curtailing fuel petroleum shipments to the North.

Trump also called for GOP lawmakers to quickly finish work on a tax overhaul bill. He also laid out his plans for how he will shape the legislative agenda early next year.

The White House will submit to Congress a welfare overhaul plan “very shortly” after GOP lawmakers wrap up their tax overhaul push, Trump said.

“We’re looking very strongly at welfare reform,” he told reporters.

Plans on health care and infrastructure also will be headed to Capitol Hill in the new year, the president said.