North Korea carried out its strongest-ever nuclear test Sunday, just days after the U.S. and South Korea wrapped up their massive joint military drills on the Korean Peninsula. North Korea has long objected to the annual drills, which include tens of thousands of troops. North Korea claims it tested a hydrogen bomb, although experts have disputed this claim.

On Monday, the U.N. Security Council met to address the test. U.S. Ambassador Nikki Haley accused North Korea of “begging for war.” President Trump tweeted, “The United States is considering, in addition to other options, stopping all trade with any country doing business with North Korea.” Experts say this proposal is next to impossible, since ceasing trade with China, Brazil, Germany, Mexico and other countries would be an economic catastrophe for the U.S.

Trump also blasted South Korea for being open to initiating peace talks with the North, tweeting, “South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!” Trump is also preparing to withdraw from a trade agreement between the U.S. and South Korea.