A lawyer for the Ukraine whistleblower, whose complaint document triggeredthe House impeachment inquiry of President Donald Trump, has sent a letter to the White House warning the President to “cease and desist” attacking his client.

“I am writing out of deep concern that your client, the President of the United States, is engaging in rhetoric and activity that places my client, the Intelligence Community Whistleblower, and their family in physical danger,” Andrew Bakaj wrote to White House counsel Pat Cipollone in a Thursday letter obtained by CNN’s Anderson Cooper.

“I am writing to respectfully request that you counsel your client on the legal and ethical peril in which he is placing himself should anyone be physically harmed as a result of his, or his surrogates’, behavior,” he said.

READ: Whistleblower lawyer’s letter to White House

Trump has repeatedly attacked the whistleblower and tried to discredit the individual, saying he, Trump, deserves to “meet his accuser” and has demanded the whistleblower’s identity be revealed. The President has also accused the whistleblower of partisanship though Trump said he had no personal knowledge of the person’s identity.

The whistleblower’s complaint alleges Trump abused his official powers “to solicit interference” from Ukraine in the 2020 election and that the White House took steps to cover it up. Trump has denied any wrongdoing.

A rough transcript released by the White House shows Trump repeatedly pushed Ukrainian President Volodymyr Zelensky to investigate former Vice President Joe Biden, Trump’s potential 2020 political rival, and his son Hunter Biden. There is no evidence of wrongdoing by Joe or Hunter Biden.

READ: The transcript of Trump’s July 25 call with Zelensky

Many of the central claims from the whistleblower’s complaint have been corroborated by testimony from Trump administration officials and the partial transcript of the July 25 call between Trump and Zelensky, which was released by the White House.

READ: The whistleblower complaint regarding Trump and Ukraine

In his letter, Bakaj cites Trump’s recent comments to reporters that they’d “be doing the public a service” if they reported the name of the whistleblower as well as his comments in September that whoever provided the whistleblower with information about his call with the Ukrainian President is “close to a spy,” adding that in the old days spies were dealt with differently.

“These are not words of an individual with a firm grasp of the significance of the office which he occupies, nor a fundamental understanding of the significance of each word he articulates by virtue of occupying that office,” Bakaj wrote.

The letter to Cipollone also states that “should anyone be physically harmed, my co-counsel, Mark Zaid, and I will not hesitate to take any and all appropriate action against your client. Those who are complicit in this vindictive campaign against my client, whether through action or inaction, shall also be responsible, be that legally or morally.”

Earlier Thursday, the whistleblower’s legal team accused House Republicans of implementing a “deflective partisan strategy” after Rep. Jim Jordan, an Ohio Republican, announced his party plans to request to bring in the anonymous individual to testify publicly – an option that has long been a nonstarter.

Accusations of partisanship have only been fueled by the Republicans submitting a request they know will almost certainly be denied by Democrats under House rules, while not yet responding to an offer from the whistleblower’s legal team that would allow them to submit written questions to the individual, an option the legal team views as a compromise.

Zaid and House Democrats have argued that the whistleblower’s identity is irrelevant at this stage in the proceedings due to testimony from several witnesses corroborating and expanding on allegations contained in the initial complaint.

CNN’s Zachary Cohen and Pamela Brown contributed to this report.