President Trump designates North Korea a 'state sponsor of terror'

President Donald Trump announced Monday his intent to again formally designate North Korea a "state sponsor of terror" - a move designed to ramp up pressure on the rogue nation's aggressive acts in the region and further development of its nuclear program.

The State Department's current list of state sponsors of terrorism includes Iran, Sudan and Syria and functions as a sort of sanctions blacklist against countries that the U.S. has deemed "repeatedly provided support for acts of international terrorism."

"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 at the White House on Monday. "This designation will impose further sanctions and penalties on North Korea and related persons and supports our maximum pressure campaign to isolate the murderous regime."

North Korea had been on the list for 20 years until 2008, when then-President George W. Bush removed the country in hopes it would jump-start peace talks.

The Trump administration came under increasing pressure to return the country to the list after North Korea's most recent nuclear test and the death of American Otto Warmbier in June after being imprisoned in the country.

Trump expressed anger at the time over North Korea's treatment of Warmbier and evoked his memory Monday in announcing his decision.

"As we take this action today, our thoughts to turn to Otto Warmbier, a wonderful young man, and the countless others so brutally affected by the North Korean oppression," Trump said.

Speaking at the White House press briefing Monday, Secretary of State Rex Tillerson said the move is not designed to signal to North Korea that diplomacy is off the table.

"We still hope for diplomacy ... The timing of this is just one of us concluding the process," he said. "This just continues to tighten the pressure on the Kim [Jong Un] regime, all with an intention to have him understand this is only going to get worse until you are ready to come and talk."

Trump said earlier Monday that the Treasury Department will announce additional sanctions on Tuesday before his departure for Florida for Thanksgiving. Neither he nor Tillerson would divulge details of the measures.

Tillerson said that oil restrictions were having an effect on North Korea but that the country has "an enormous capacity to withstand a lot."

"I don't want to say that one action is all it would take to get them to the table," he said.

Asked whether he believed the designation could provoke Kim, disrupting a run of more than two months without a missile test, Tillerson said only that he hopes the stretch continues, adding that the the administration gave careful consideration to the designation.

"We're hopeful that he continues this quiet period. That's our objective, is that he continue to be quiet, as well," he said. "This designation, as I said, is one that we're required to undertake from time to time, and we've been monitoring the situation. We wanted to be sure we had sufficient evidence before making the designation, so this is a process that started actually several months ago."

ABC News' Adam Kelsey contributed to this report.