HELSINKI (AP) — The U.S. ambassador to Estonia has resigned over frustrations with President Donald Trump's comments about the European Union and his treatment of Washington's European allies.

In a private Facebook message posted Friday, James D. Melville wrote: "For the President to say EU was 'set up to take advantage of the United States, to attack our piggy bank,' or that 'NATO is as bad as NAFTA' is not only factually wrong, but proves to me that it's time to go."

Melville was referring to Trump's recent comments at news conferences and on social media.

Melville stressed that a U.S. forei...