The New York Times reported German Chancellor Angela Merkel showed little indication she was warming to the idea to collectivize the eurozone's debt or to use European bailout funds to help Spain and Italy.
"The euro is here to stay, and we all mean it," Italian Prime Minister Mario Monti told a news conference after meeting with Merkel, Spanish Prime Minister Mariano Rajoy and French President Francois Hollande.
The meeting came ahead of next week's EU summit in Brussels.
Monti said consequences will be grave if no long-term solution to the crisis is forged.
"There would be progressively greater speculative attacks on individual countries, with harassment of the weaker countries" if the June 28-29 summit in Brussels of all 27 EU leaders doesn't reach a comprehensive solution, Monti told British newspaper The Guardian and a group of leading European newspapers.
The spiral could likely become more political than economic, he said.
The summit is widely expected to tackle long-term plans for closer fiscal and banking integration.
If the summit doesn't come up with a so-called grand bargain, "a large part of Europe would find itself having to continue to put up with very high interest rates that would then impact on the states and also indirectly on firms," Monti said. "This is the direct opposite of what is needed for economic growth."