European Commission President Jose Manuel Barroso has stepped in to try and defuse a growing European row over cross-border energy company takeovers.
Mr Barroso says EU members should not put up economic barriers
He told Italy and France to stop using nationalist rhetoric in a dispute over the merger of Gaz de France and Suez.
The French merger was announced last Sunday, just days after Italy's Enel had hinted at an offer for Suez.
France has since vowed to continue defending its energy sector, while Italy wants Brussels to intervene.
"The suggestion is sometimes that member states are defending themselves against each other," said Mr Barroso.
"We are not going to be able to meet the challenges facing us if we take a nationalist approach."
Paris has strongly backed the 72bn euros (£49bn) deal, arguing it conforms with its policy of protecting businesses in areas vital to national security - such as energy, biotechnology and data security - from foreign takeover.
'Close the Commission'
But French Prime Minister Dominique de Villepin rejected charges that France was closed to foreign-based businesses.
"One French worker in seven works for a foreign group. That is more than in Germany, more than in the United Kingdom, more than in the Netherlands," he said.
Giulio Tremonti is urging Brussels to intervene
But the Italian government has stepped up its attack on the deal, saying that Enel would present its case for acquiring Suez to the Commission by Thursday.
"If the Commission does not act, my advice would be for it to close down because of a failure to meet its mandate."
The Commision has said it will not intervene unless it is given evidence that the proposed merger breaks competition rules.