The council’s North Korea sanctions committee acted on a request by the United States, designating 21 shipping companies — including five based in China — 15 North Korean ships, 12 non-North Korean ships and a Taiwanese man.

The move comes days after Kim met Chinese President Xi Jinping and an announcement that the North Korean leader would meet South Korean President Moon Jae-in on April 27. He is also scheduled to meet U.S. President Donald Trump some time in May.

While Trump has agreed to meet Kim, he tweeted on Wednesday that “maximum sanctions and pressure must be maintained.”

Tension over North Korea’s tests of nuclear weapons and ballistic missiles surged last year and raised fears of U.S. military action in response to the North’s threat to develop a nuclear weapon capable of hitting the U.S. mainland.

But the situation has eased significantly since North Korea sent athletes to the Winter Olympics in South Korea in February.

U.S. Ambassador to the United Nations Nikki Haley said the U.N. sanctions designations — the largest agreed by the council’s committee — were aimed at shutting down North Korea’s illegal smuggling activities to obtain oil and sell coal.

“The approval of this historic sanctions package is a clear sign that the international community is united in our efforts to keep up maximum pressure on the North Korean regime,” she said in a statement.

The list was part of a request by Washington late last month for 33 ships, 27 shipping companies and the Taiwanese man to be sanctioned. China delayed that bid on March 2, but did not give a reason. The 15-member committee works by consensus.

Washington then proposed a shortened list on Thursday, which was unanimously agreed by the committee on Friday.

The 12 non-North Korea ships are now subjected to a global port ban and must be deregistered, while the 15 North Korean ships are subjected to an asset freeze and 13 of those a global port ban.

The Taiwanese man, Tsang Yung Yuan, is accused of coordinating “North Korean coal exports with a North Korean broker operating in a third country, and he has a history of other sanctions evasion activities,” according to the U.N. listing. He is subjected to an asset freeze and travel ban.

The assets of the 21 shipping companies, which include businesses based in the Marshall Islands, Singapore, Panama and Samoa, must now be frozen.

The U.N. Security Council has unanimously boosted sanctions on North Korea since 2006 in a bid to choke off funding for Pyongyang’s nuclear and ballistic missile programs, banning exports including coal, iron, lead, textiles and seafood, and capping imports of crude oil and refined petroleum products

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