The devastation wreaked by the deadly storm, described as the worst natural disaster in US history, could turn out to be higher than estimated, a Munich Re spokesman said.

"We can't rule out that the insured losses will be a lot higher than anticipated," he said.

On Tuesday, Munich Re had estimated the damage at 16-20 billion dollars (12-16 billion euros), but higher numbers were already circulating in the US.

And that meant Munich Re's own exposure to the catastrophe could be higher than the 400 million euros originally earmarked, the spokesman said.

Nevertheless, the reinsurance giant was sticking to its target of net return on equity of 12 percent, even if that goal would "more difficult to attain," he said.

The figure would be equivalent to net profit of 2.5 billion euros this year, up from 1.83 billion euros in 2004.