The White House says President Trump plans to meet with Ukrainian President Volodymyr Zelenskyy and Syrian President Ahmad al-Sharaa.
Denmark, Norway, Sweden, France, Germany, the United Kingdom, the Netherlands and Finland would face the tariff.
Trump's comments came hours before Vice President JD Vance was to host Danish and Greenlandic officials for talks.
Presidents Trump and Putin are holding a press conference following their meeting in Alaska to discuss ending the Russia-Ukraine war.
NATO Secretary-General Mark Rutte is in Washington for talks with President Donald Trump, Secretary of State Marco Rubio and others.
A dozen leaders from Europe and Canada are in Ukraine’s capital to mark the third anniversary of Russia’s invasion.
President Trump plans to cover a range of issues in his meeting with Japanese Prime Minister Shigeru Ishiba.
Putin’s endorsement of the new nuclear deterrent policy comes on the 1,000th day after he sent troops into Ukraine, on Feb. 24, 2022.
Russia also is slowly pushing Ukraine’s outnumbered army backward in the eastern Donetsk region.
According to a Harris aide, Harris discussed the importance of a peaceful transfer of power with Trump.