Germany forced the pace Friday as European leaders scrambled to resolve the deep political crisis over the EU constitution, with Chancellor Gerhard Schroeder scheduling a series of meeting with EU leaders.

The bloc is suffering one of the biggest crises in its history after voters in France and the Netherlands rejected the first text of its kind, shattering efforts to streamline ground rules for the ever-expanding EU membership.

With polls in Denmark suggesting it, too, would reject the treaty, Britain appearing ready to put its promised referendum on ice and Luxembourg's prime minister forced to put his job on the line, Schroeder has emerged -- almost by default -- as a mediator.

"I will not give up in working for this constitution, for a united Europe which we need," Schroeder said on Thursday, after crisis talks in Luxembourg with the European Union's current presidency.

On Friday, after talks with Romanian Prime Minister Calin Tariceanu, whose nation wants to join the bloc in 2007, Schroeder said it was "totally untrue" to suggest that EU enlargement should stop.

Concerns the bloc is growing too big too quickly have been cited by voters who have rejected the constitution.

With French President Jacques Chirac compromised by the decisive "no" from his electorate in Sunday's French referendum, Schroeder -- the other half of the Franco-German engine at the heart of Europe -- has been forced to lead the salvage operation.

He followed his flying visit to Luxembourg by dashing back to Berlin for a brief meeting with Irish Prime Minister Bertie Ahern.

Chirac is due to fly in Saturday for a working dinner in the German capital with Schroeder and the two will meet again five days later in Paris.

Meanwhile Schroeder will squeeze in another meeting with Luxembourg Prime Minister Jean-Claude Juncker next week as well.

Then British Prime Minister Tony Blair visits on June 13, just ahead of a summit of EU leaders in Brussels on June 16-17 at which they will discuss what to do next.

In France, new Foreign Minister Philippe Douste-Blazy insisted France would remain "at the heart of European integration."

"We are obviously in a difficult situation after two negative referendums," said Douste-Blazy, part of a new government appointed by Chirac in the wake of Sunday's defeat.

While Germany has ratified the constitution, albeit without a referendum, Schroeder and the other defenders of the constitution appeared to be facing an increasingly difficult task to hold the treaty together.

Government sources in London are quoted as saying Britain will announce on Monday that it is to put its referendum, planned for next year, on hold.

With Luxembourg the next country to hold a popular vote on the constitution on July 10, Juncker declared he would resign if voters rejected it.

Juncker was speaking after opinion polls showed a surge of support for the "no" camp in Luxembourg, the tiny state which has been a staunch supporter of the European project.

"It is a question of basic decency towards the voters of Luxembourg," the premier told reporters. "If there is a 'no,' it is not the people who have to quit. It is up to me to go."

In addition, Juncker confirmed that the EU charter, which aims to prevent decision-making gridlock in the expanding bloc, would be definitively dead if more than five EU countries give it the thumbs down.

In Denmark, public opinion has swung against ratification of the treaty in the wake of the French and Dutch results, two opinion polls showed.

Both Danish polls give the "no" camp a clear lead for the first time, less than four months ahead of a September 27 referendum.

But Schroeder insisted the process of ratifying the constitution should be allowed to continue, arguing that all 25 EU member states had been promised a right to vote on it.

In Brussels, a spokeswoman for EU foreign policy chief Javier Solana said the crisis might make it "a little bit more complicated" for Balkans nations hoping to join the bloc.

Meanwhile the Estonian parliament postponed its ratification of the treaty until the autumn for legal reasons, officials said, but denied the delay was influenced by the French and Dutch results.