Berlin  - Speaking in Berlin before the G20 summit, German Chancellor Angela Merkel warned anew against any reversion to protectionism as nations struggle to avoid the economic crisis.

"It would be the worst answer to this situation," she said, adding that she was bound for London "with a mixture of optimism and concern." She said the world faced the moment of decision.

"My concern is that we may not react forcefully enough," Merkel said, and referred to Berlin's pressure for robust international regulation of financial markets. "We have to ensure with all our might that such a crisis never happens again." (dpa)