Sen. Bob Menendez (N.J.), the top Democrat on the Senate Foreign Relations Committee, called for an “immediate briefing” from the administration on communications released by House Democrats on Tuesday suggesting former Ambassador to Ukraine Marie Yovanovitch was under surveillance by Trump associates before her removal.

“These disturbing messages indicate that Ambassador Yovanovitch’s movements may have been closely tracked, for at a minimum, over a series of days in late March 2019. Notably, this was the same time frame that a packet of disinformation, the contents of which smeared Ambassador Yovanovitch, made its way into the hands of senior officials at the State Department, including the Secretary, and as a series of articles were published that made false attacks against her,” Menendez wrote in a letter to Assistant Secretary of State Michael Evanoff.

In the records released by lawmakers on Tuesday, Republican congressional candidate Robert Hyde texted Lev Parnas, an associate of President Trump's personal attorney Rudy Giuliani who was indicted last year, “Wow. Can’t believe Trumo hasn’t fired this bitch. I’ll get right in that” in reference to Yovanovitch.

Hyde suggested in the communications that Yovanovitch's movements were being monitored, texting Parnas, “They will let me know when she’s on the move.”

“I demand an immediate briefing and accounting by you and all relevant officials about what the Department knew about any of these efforts to track Ambassador Yovanovitch’s whereabouts while she served in Kyiv, including Embassy officials and the Regional Security Officer at post; what steps the Department took at the time to ensure her safety; and the steps it has taken since then to ensure her safety and the safety of all U.S. personnel stationed in Kyiv,” Menendez wrote.

The Hill has reached out to the State Department for comment.

The messages, which also detail Parnas's role in trying to pressure the Ukrainian government to open investigations that would be beneficial to Trump, have been seized on by Democrats who say they "dramatically underscore" the need to admit new witnesses and documents in Trump's impeachment trial.

In the letter, Menendez also claimed the State Department had yet to address concerns he raised in two letters sent in November regarding potential risks to the safety of diplomats who testified before Congress in the House’s impeachment hearings, calling the lack of response “disturbing.”

“I trust that you will treat this request with utmost urgency, and swiftly respond to this as well as my prior requests regarding the safety and security of Department employees,” he wrote.