WH official tells me Nielsen resigned. But clearly Trump was unhappy with her for many months. Our @JDiamond1 has obtained her resignation letter.

— Jim Acosta (@Acosta) April 7, 2019

Nielsen was not planning to resign when she walked into her meeting with Trump today, but she was prepared for the possibility. Here is her resignation letter, per a source close to Nielsen: pic.twitter.com/ElyTiwbYuR

— Jeremy Diamond (@JDiamond1) April 7, 2019