NEW YORK — President Trump lashed back Friday at North Korea’s leader, calling Kim Jong Un a “madman” whose regime will be “tested like never before” amid new U.S.-imposed financial sanctions.

The latest economic pressures announced Thursday come as the Trump administration seeks to build international support for more aggressively confronting the rogue nation, whose escalating nuclear and ballistic missile capabilities have reached what U.S. officials consider a crisis point.

The new penalties seek to leverage the dominance of the U.S. financial system by forcing nations, foreign companies and individuals to choose whether to do business with the United States or the comparatively tiny economy of North Korea. U.S. officials acknowledged that like other sanctions, these may not deter North Korean leader Kim Jong Un’s drive to threaten the United States with a nuclear weapon, but are aimed at slowing him down.

Kim on Thursday reacted angrily to Trump’s remarks and actions this week, calling the president a “mentally deranged U.S. dotard” and Trump’s earlier speech at the U.N. “unprecedented rude nonsense.” Kim said he was now thinking hard about how to respond.