President Trump on Friday announced what he and his administration are billing as the United States’ “largest ever” tranche of sanctions against North Korea.

Friday’s sanctions are aimed at targeting North Korea’s ability to evade international sanctions and conduct illicit maritime activities that facilitate coal and fuel transports by designating 27 shipping and trade companies, 28 vessels and one individual.

“Today I am announcing that we are launching the largest-ever set of new sanctions on the North Korean regime,” Trump said during his speech at the Conservative Political Action Conference. “The Treasury Department will soon be taking new action to further cut off sources of revenue and fuel that the regime uses to fund its nuclear program and sustain its military by targeting 56 vessels, shipping companies and trade businesses that are assisting North Korea in evading sanctions.”

In conjunction with the new sanctions, the Treasury and State departments and the U.S. Coast Guard are issuing a global shipping advisory that warns of “very significant consequences” for helping North Korea evade sanctions and outlines some of the steps its ships take to do so, administration officials told reporters on a background call.

North Korea’s ability to evade international sanctions on the high seas has garnered increasing attention, as the sanctions noose around Pyongyang is as tight as it’s ever been with most key exports now banned.

In particular, China and Russia’s alleged role in helping North Korea evade sanctions has come under increasing scrutiny. Just this week, Japan said it saw a ship with Chinese writing taking part in a ship-to-ship transfer in the East China Sea that Tokyo “strongly suspects” violates sanctions.

The shipping advisory will describe efforts to conceal North Korea-flagged ships’ identities, such as the ships painting over their real names and disabling their automatic identification systems that are meant to be collision avoidance systems.

“By targeting North Korea’s ability to ship goods from international waters, we are very much closing in on one of the primary means that the regime uses to sustain and finance itself,” an administration officials said. “The president has made it loud and clear to companies around the world that if they choose to help finance North Korea and its nuclear ambitions, they will not do business with the United States.”

The new sanctions target ships and businesses from all over the world, including North Korea, China, Singapore, Taiwan, Hong Kong, Marshall Islands, Tanzania, Panama and Comoros.

No entities from Russia are being sanctioned Friday despite Moscow’s alleged role in helping Pyongyang, though administration officials noted Russian entities have been sanctions in the past.

Friday’s announcement comes as Trump’s daughter and adviser, Ivanka Trump, lands in South Korea to lead the U.S. delegation for the closing ceremonies of the Winter Olympics.

Administration officials have said Ivanka Trump will not meet with the North Korean delegation while there, despite the fact that Vice President Pence had planned to secretly meet with the North before the meeting was scrapped.

Pence led the U.S. delegation to the opening ceremony and spent his travels through Asia beforehand sending a tough-on-Pyongyang message, including telegraphing the sanctions that were announced Friday.

This week, his office revealed he planned to secretly meet with Kim Jong Un’s sister in South Korea, but the meeting was ultimately canceled. Pence’s office suggested Pyongyang was irked by Pence refusing to soften his tone on North Korea.

Like Trump’s speech Friday, Pence’s speech Thursday at CPAC focused in on North Korea. He specifically targeted the U.S. media’s coverage of North Korea at the Olympics, which he described as “fawning.”

“For all those in the media who think I should have stood and cheered with the North Koreans, I say: The United States of America doesn’t stand with murderous dictatorships. The United States of America stands up to murderous dictatorships,” Pence said to loud cheers.