Federal Reserve Governor Lisa Cook said Wednesday that she has “no intention of being bullied to step down from my position because of some questions raised in a tweet.”

The statement from Cook came after the head of President Donald Trump’s housing regulatory agency said Cook should resign or be fired for cause over what he claimed was evidence of “mortgage fraud” by the central bank official.

“To be honest, I think she needs to resign quickly,” Bill Pulte, director of the Federal Housing Finance Agency, said of Cook on CNBC’s “Money Movers.”

“I think she will have to resign, or I think she will be fired,” he said.

The remarks came hours after Trump, reacting to a letter Pulte sent to the Department of Justice asking it to criminally investigate Cook, wrote in a social media post that the governor “must resign, now!!!”