German Chancellor Angela Merkel rejected French calls to deploy the European Central Bank as a crisis backstop, defying global leaders and investors calling for more urgent action to halt the turmoil.

As the crisis sent borrowing costs in core economies outside Germany to euro-era records, Merkel listed using the ECB as lender of last resort alongside joint euro-area bonds and a "snappy debt cut" as proposals that won't work.

"I'm convinced that none of these approaches, if applied right now, would bring about a solution of this crisis," Merkel said in a speech in Berlin today. "If politicians believe the ECB can solve the problem of the euro's weakness, then they're trying to convince themselves of something that won't happen."