Steps by US President Donald Trump to remove Federal Reserve chairman Jerome Powell or Fed governor Lisa Cook would represent a "very serious danger for the US economy and the world economy", said European Central Bank president Christine Lagarde on Monday.

Trump is seeking to remove Federal Reserve governor Lisa Cook in a move that critics say aims to fill the central bank with officials who will support his calls for lower interest rates.

Lagarde told France's Radio Classique that it would "very difficult" for Trump "to completely swing the majority" of the Fed's policymaking body in his favour.

But, she said, "if he were to succeed, it would be a very serious danger for the US economy and for the world economy."

"If US monetary policy were no longer independent and instead dependent on the dictates of this or that person, then I believe that the effect on the balance of the American economy could, as a result of the effects this would have around the world, be very worrying, because it is the largest economy in the world."

She noted that the central bank's policies affect price stability and aims to ensure "optimal" employment. (Reuters/AFP)