BERLIN—Chancellor Angela Merkel roundly rebuffed U.S. President Barack Obama's call for Germans to aid the global recovery by spending more and relying less on exports, even as she warned that Europe's own financial crisis is far from over.

In an interview with The Wall Street Journal in her Berlin chancellery, an unapologetic Ms. Merkel said the nations that share the beleaguered euro have merely bought some time to fix the flaws in their monetary union. She called on the Group of 20 industrial and developing nations meeting...