In an extraordinary escalation of a months-long attack on the independence of the Federal Reserve, federal prosecutors have launched a criminal investigation into Federal Reserve Chair Jerome Powell, he confirmed in a statement Sunday night.

The investigation is related to Powell’s testimony earlier this year about the multi-year renovation of the Federal Reserve buildings, Powell said in a video message released by the Fed.

But Powell says it’s clear the investigation is ultimately part of President Donald Trump’s administration’s increasingly hostile push to pressure the Fed to lower interest rates.

“This is about whether the Fed will be able to continue to set interest rates based on evidence and economic conditions — or whether instead monetary policy will be directed by political pressure or intimidation,” Powell said.

In a statement to ABC News, a spokesperson for Attorney General Pam Bondi said, “The Attorney General has instructed her U.S. Attorneys to prioritize investigating any abuse of taxpayer dollars.”

This is a developing story. Please check back for updates.