Under heavy pressure to restore confidence in the euro zone following a dramatic market slump, President Nicolas Sarkozy and Chancellor Angela Merkel stopped short of increasing the bloc's rescue fund but vowed to stand side-by-side in defending the euro and laid the groundwork for future fiscal union.

Their message was that the focus should be on further economic integration rather than signing bailout checks, and suggested that straying from euro zone rules and fiscal targets would no longer be tolerated.

"We have exactly the same position on euro bonds," Sarkozy told a joint news conference with Merkel after their talks.

"Euro bonds can be imagined one day, but at the end of the European integration process, not at the beginning."

But many experts said the measures would fail to assuage markets, which believe a common bond is the only way to ensure affordable financing for euro zone members struggling with debt.

US stocks dropped more than 1 percent and the euro slid as the proposals failed to ease worries about a debt crisis markets fear is spreading to the euro zone's core. Traders had hoped for signals that the issuance of common euro bonds, or an increase of the EFSF, were live options.

The statement by the two leaders reflects deep hostility, among voters in northern Europe tired of bailing out the south at a time of austerity at home. That is particularly true in Germany, where growth slowed to almost zero in the second quarter.