U.S. President Donald Trump’s long-running ire with Jerome Powell reached a fever pitch this week, with the president openly musing about dismissing the Fed chair over his interest-rate decisions as some advisers have been counseling restraint.

Trump has been asking those around him about the possibility of removing the Federal Reserve chair, according to people familiar with the matter. Moreover, Powell angered some Trump allies by giving a speech Wednesday justifying the Fed’s cautious rates approach as the president’s trade war unnerves markets, people said.

While Trump hasn’t outright said he will oust the central banker, merely asking about someone’s job status has traditionally been a tell-tale sign he is considering sacking a government official. But moving against a Fed chair would be far more significant for the world economy than Trump’s past personnel changes, sending shock waves through an economic system already rattled by the U.S. president’s decision to raise tariffs to their highest levels in a century.