US Federal Reserve Governor Lisa Cook’s lawyer said she will launch a court challenge against US President Donald Trump’s effort to fire her.

“President Trump has no authority to remove Federal Reserve Governor Lisa Cook,” lawyer Abbe Lowell said in a statement emailed to reporters.

“His attempt to fire her, based solely on a referral letter, lacks any factual or legal basis. His reflex to bully is flawed.”

“We will take whatever actions are needed to prevent his attempted illegal action,” Lowell said.

Financial markets worldwide have been rattled by Trump’s unprecedented move to remove Cook and a sharp escalation in his effort to exert greater control over what has long been considered an institution independent from day-to-day politics.