The eurozone faces grave consequences if a summit of European leaders doesn\'t produce a long-term solution to the financial crisis, Italy\'s prime minister said. \"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 European Union leaders doesn\'t reach a comprehensive solution, Mario Monti told the British newspaper The Guardian and a group of leading European newspapers. The spiral could likely become more political than economic, he said. Monti said he would hold talks in Rome Friday with German Chancellor Angela Merkel, French President Francois Hollande and Spanish Prime Minister Mariano Rajoy, in the hope that the eurozone\'s four biggest economies can pave the way for a breakthrough at next week\'s meeting. 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.\"