French President Nicolas Sarkozy promised on Sunday that euro zone countries would help Greece if its financial problems worsened and vowed a crackdown on market speculators whom the Greeks blame for their woes.

He was speaking after talks with Greek Prime Minister George Papandreou, who is looking to secure pledges of support from European capitals that will reassure markets and lower the debt-stricken country's high borrowing costs.

If Greece needs help, we will be there, Sarkozy said at a joint news conference.

The main actors on the European stage are decided to do whatever is needed to make sure Greece is not isolated, he added, declining to give precise details of any aid plans but stressing that his economy minister was drawing up measures.

Christine Lagarde, in tandem with her colleagues in the euro zone and in Europe ... is working on a certain number of precise measures if Greece needs them, he said.

Papandreou met German Chancellor Angela Merkel and Luxembourg Prime Minister Jean-Claude Juncker on Friday. He had been hoping for specifics of a possible aid package and on Sunday told reporters he saw the outlines of a plan.

After my meetings more specific ways are beginning to emerge about how to deal with any possible borrowing problems, he told reporters. He is due to fly to Washington later on Sunday for meetings with U.S. leaders.

Sarkozy talked to Merkel earlier in the day by telephone and said that France, Germany and Greece were ready to take concerted action against market speculation aimed at Greece.

Greece unveiled a 4.8 billion euro ($6.52 billion) austerity package last week to hack back its double-digit deficit, and blames market speculators, who are betting on a possible Greek default, for pushing up the cost of debt servicing.

Sarkozy agreed that speculators were artificially hiking the cost of borrowing for Greece and said they needed to be tackled.

This problem could hit lots of countries if we don't come up with a collective response, he said.

Concrete, precise means exist (to combat speculators) which we won't be communicating tonight ... but which at the given moment will show that Greece is not just being supported politically, but also in all aspects of any eventual requests.

(Reporting by Harry Papachristou; writing by Crispian Balmer; Editing by Jon Boyle)