President Trump escalated his feud with the husband of White House counselor Kellyanne Conway, calling him “a stone cold LOSER & husband from hell!”

Trump’s broadside on Twitter came after George Conway, a conservative lawyer and frequent critic of the president, publicly questioned the president’s mental health in recent days.

George Conway responded less than 20 minutes later.

“You seem determined to prove my point. Good for you!” he wrote on Twitter, adding: “#NarcissisticPersonalityDisorder.”

In a subsequent tweet directed at Trump, he added: “You. Are. Nuts.”

George Conway has pushed back on several assertions in Trump’s tweet, including the notion that Trump decided not to give him a job.

Conway said Tuesday that he opted against working in the Justice Department after Trump offered him a position heading the civil division because he watched Trump attack the department’s leaders and then fire James B. Comey as FBI director in May 2017.

On Wednesday, Conway shared a letter he wrote to Trump, dated May 31, 2017, in which he thanked Trump for selecting him for the job but said he was backing out.

“I have reluctantly concluded, however, that for me and my family, this is not the right time for me to leave the private sector and take on a new role in the federal government,” Conway wrote. “Kellyanne and I continue to support you and your Administration, and I look forward to doing so in whatever way I can from outside government.”

It was unclear what Trump meant by his assertion in his tweet that Kellyanne Conway had a role in denying her husband a job.

Conway said Tuesday’s interview that he has had a number of notable interactions with Trump over the past decade, often concerning legal representation and sensitive legal matters since Trump became president.

Wednesday was the second consecutive day that Trump has used Twitter to attack George Conway. In a much shorter tweet Tuesday, he called him a “loser.”

Kellyanne Conway did not respond to a request for comment Tuesday, but she said on Monday that she did not share her husband’s concerns about Trump’s mental health.

George Conway has been a persistent critic of Trump’s policies and actions, frequently going on Twitter to question whether the president is operating within the Constitution and other accepted boundaries. But the criticism recently has become more personal, and he has often attacked Trump just after his wife has defended the president on television.

In tweets Monday, Conway included images from the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, including pages with diagnostic criteria for “narcissistic personality disorder” and “antisocial personality disorder.”