Fiona Hill might be a major threat to President Trump.

Hill, who previously served as Trump's top adviser to Russia, was hired in March 2017 as an ally to then-National Security Adviser H.R. McMaster and a fierce critic of Russian President Vladimir Putin. And as a story of her first time meeting Trump reveals, she's seemingly unafraid to hurt the president's feelings — something that could prove notable as she testifies for Congress on Monday.

As The Washington Post reported in 2017, Hill's hiring was "a reassuring selection among Russia hard-liners." But as the Post continues, Hill's "relationship with Trump, however, was strained from the start."

In one of her first encounters with the president, an Oval Office meeting in preparation for a call with Putin on Syria, Trump appeared to mistake Hill for a member of the clerical staff, handing her a memo he had marked up and instructing her to rewrite it. When Hill responded with a perplexed look, Trump became irritated with what he interpreted as insubordination, according to officials who witnessed the exchange. As she walked away in confusion, Trump exploded and motioned for McMaster to intervene. [The Washington Post]

Things got even worse for Hill "when she was forced to defend members of her staff suspected of disloyalty" after Trump's meeting with Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergey Kislyak was leaked, per the Post. Read more about Hill and Trump's troubles at The Washington Post. Kathryn Krawczyk