House Speaker Nancy Pelosi on Thursday said she would be happy to start working with "extremely stable genius" President Donald Trump once he starts acting more presidential.

" When the 'extremely stable genius' starts acting more presidential, I'll be happy to work with him on infrastructure, trade and other issues," Pelosi said in a tweet.

This came a day after Trump signaled he did not want to work with Democrats on an array of issues until they stopped investigating him on various matters.

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House Speaker Nancy Pelosi on Thursday escalated the war of words with President Donald Trump in a tweet mocking him as an "extremely stable genius."

"When the 'extremely stable genius' starts acting more presidential, I'll be happy to work with him on infrastructure, trade and other issues," Pelosi said.

Trump in the past referred to himself as a "very stable genius" and earlier in the day on Thursday called himself an "extremely stable genius."

The House Speaker was responding to a tweet quoting the president as calling her "a mess" after she suggested Trump was not well and needs an "intervention."

"I wish that his family or his administration or his staff would have an intervention for the good of the country," Pelosi said in her weekly news conference on Thursday. She also suggested the president might benefit from a leave of absence.

Read more: 'Impeachment is inevitable': More Democrats push for impeachment as Nancy Pelosi accuses Trump of 'engaging in a cover-up'

This all came a day after Trump stormed out of a meeting with Democratic leaders that was meant to focus on infrastructure.

Subsequently, Trump held a supposedly impromptu press conference to bash the array of investigations House Democrats have launched into everything from the president's business dealings to whether he obstructed justice amid special counsel Robert Mueller's probe into Russian election interference.

During the press conference, Trump signaled he did not want to work with Democrats on infrastructure or any other issues until they stop investigating him. The president referred to the various congressional probes focusing on him as "phony investigations."

Read more: Nancy Pelosi: 'The president of the United States is engaged in a cover-up'

This also came after Pelosi accused Trump of engaging in a "cover-up" over his administration's various attempts to stonewall congressional investigations, and following a meeting with the Democratic caucus in which the prospect of impeaching the president was discussed.

Trump was quite perturbed by the impeachment discussions, decrying Democrats for discussing the "I-word."