The leaders of Germany and France pledged on Thursday to work together on financial regulation and the euro zone crisis after European discord over debt and new market rules rattled investors worldwide.

German Chancellor Angela Merkel telephoned French President Nicolas Sarkozy after a public rift over Berlin's unilateral ban on some types of speculative stocks and bond trading sapped confidence in the euro and sent investors seeking safer havens.

We don't have any disagreements together, Sarkozy said when asked about ties between France and Germany. He was speaking at a joint news conference with British Prime Minister David Cameron, on his first trip abroad since taking office.

A German spokesman said Sarkozy and Merkel agreed to present joint proposals for a European economic growth strategy to EU leaders in mid-June and to coordinate positions at a G20 summit later next month on a new global financial rulebook. Sarkozy will visit Berlin on June 7 to discuss coordination, he said.

The euro, which had plunged to a four-year low after the German move on Wednesday, gained nearly a cent to trade at around $1.25 on news of the Franco-German telephone call.

Sarkozy earlier unveiled plans to insert a German-inspired commitment to cutting the budget deficit into France's constitution, in a move aimed both to reassure markets and to show goodwill to Berlin.

Germany and France, the co-founders of the euro, have been at odds for months over how to handle Greece's debt crisis and deeper-seated economic imbalances in the single currency area.

That discord has spread fears worldwide about the impact of Europe's debt problems on a fragile global economic recovery.

In Washington, the White House said European governments needed to take strong measures to tackle the debt crisis.

Europe is having to deal with the problems within Europe and we continue to believe those are some tough steps that are going to have to be taken, White House spokesman Robert Gibbs told reporters.

China said the euro crisis was adding to global uncertainty, a factor underlined by weakness in its own stock market.

The constitutional amendment outlined by Sarkozy was far less constraining than Germany's debt brake, which is intended to force the federal government to limit the deficit to 0.35 percent of national output by 2016.

But the fact that free-spending France is contemplating such a measure at all highlights how the debt crisis is forcing all 16 states in the euro zone to give new priority to cutting debt and deficits.

This reform will oblige each government coming out of an election to engage in a five-year path dealing with the deficit, Sarkozy told a conference, adding that governments would have to commit to a deadline for balancing public finances.

However, IMF chief Dominique Strauss-Kahn said Germany and France should not focus too quickly on cutting budget deficits.

Big countries should not slow down too quickly otherwise they will break growth, he told French television, also calling for greater coordination in Europe.

I do not think the euro zone is at risk of exploding. However, the risk is that it works poorly, the IMF boss said.


Early this month, Greece was forced to adopt draconian spending cuts and tax rises in exchange for a 110 billion euro ($135 billion) bailout from other euro zone governments and the International Monetary Fund.

Last week Spain and Portugal, struggling with high deficits that prompted market pressure on their bonds, announced fresh deficit-cutting measures. The Spanish cabinet approved a plan on Thursday aiming to save 15.25 billion euros ($18.93 billion) in 2010 and 2011.

Highly indebted Italy is planning deficit reduction steps, while France has proclaimed a three-year public spending freeze.

The euro zone crisis continued to spook markets on Thursday, with European stocks falling 2.2 percent, bringing losses so far this month to over 8 percent.

Investors worry that other euro zone countries might eventually follow Berlin's lead by banning naked short-selling in some instruments, which could hurt liquidity in those markets. In naked short-selling, a trader sells an instrument short, betting its price will fall, without first borrowing the instrument or ensuring it can be borrowed.

Fears that Europe's austerity measures could crimp world growth hit stocks globally and helped drive crude oil prices down to an eight-month low.

Germany said restoring confidence in the euro was its top priority, demanding tougher regulation and oversight to protect the single currency, as well as joint action by the European Union in withdrawing emergency economic stimulus measures.

Finance Minister Wolfgang Schaeuble said Berlin would press at a high-level EU meeting on Friday for a process permitting the orderly insolvency of states. The meeting may also discuss possible changes to the EU treaty to enforce stricter fiscal discipline, he said.

Merkel said the euro zone's problems must be tackled at their root, telling a financial conference that rules governing the single currency zone should be tightened.

But France, smarting from Germany's failure to consult it on the trading ban, said it did not agree with Merkel's comment that the euro was under threat.

I absolutely do not think that the euro is in danger, French Economy Minister Christine Lagarde told RTL radio on Thursday. The euro is a solid and credible currency.

Germany is the main EU donor in the bailout of Greece and a $1 trillion financial safety net being created for other indebted euro zone nations.

But Merkel, forced to ditch an electoral promise of 16 billion euros in tax cuts to fund the rescue packages, is under pressure within Germany after voters angered by the aid to Greece punished her coalition in a key regional election.


Jean-Claude Juncker, chairman of the forum of euro zone finance ministers, said the weakness of the euro, down more than 7 percent against the dollar in the past month, was likely due to fears economic growth in the zone would slow.

But he insisted that the markets were acting irrationally.

There is a certain reluctance to believe the Greeks can overcome the current crisis. I don't think the markets are behaving in a rational way, he told Reuters in Tokyo.

Greeks staged another 24-hour general strike on Thursday in their latest protest against austerity measures demanded by the EU and the IMF. The main protest march was smaller than a mass demonstration that turned violent last month and some workers, such as air controllers, did not join the strike.

(Additional reporting by Holger Hansen and Brian Rohan in Berlin, Emmanuel Jarry and John Irish in Paris, Renee Maltezou in Athens; Writing by Paul Taylor and Jon Boyle; Editing by Charles Dick)