(Reuters) - Germany's Angela Merkel arrived inGreece on her first visit since Europe's debt crisis erupted here three years ago, braving protests to deliver a message of support - but no new money - to a nation hammered by recession and fighting to stay in the euro.

Thousands of Greeks defied a ban on protests, gathering in Syntagma square in central Athens as Merkel's plane touched down. Two protesters dressed in German military uniforms waved a red-black-and-white swastika flag and held out their arms in the Nazi salute.

Many Greeks blame Merkel for forcing painful cuts on Greece in exchange for two EU-IMF bailout packages totaling over 200 billion euros.

Police have readied 6,000 officers, including anti-terrorist units and rooftop snipers, to provide security during the six-hour visit. German sites in the Greek capital, including the embassy and Goethe Institute, are under special protection.

Merkel was given the red carpet treatment and full military honors at Athens airport. Prime Minister Antonis Samaras greeted her with a handshake as she exited the German air force jet. A band played the German and Greek national anthems.

In the centre of Athens, the reception was less warm. On Syntagma square, banners read "Merkel out, Greece is not your colony" and "This is not a European Union, it's slavery".

"We don't want her here. Merkel go home!," said Maria Dimitriou, a 40-year-old unemployed woman who travelled to Athens from southern Greece to protest. "They've turned our lives into hell."

After steering clear of Greece for the past five years, Merkel decided to visit for several reasons.

She wants to show support for Samaras, a fellow conservative, as he struggles to impose more cuts on a society fraying at the edges after five years of recession.

At a joint appearance before the press in the afternoon, she is expected to confirm her desire to keep Greece in the euro zone, after members of her government flirted with the idea of an exit earlier this year.

With a year to go until Germany holds an election, Merkel also hopes to neutralize opposition criticism that she has neglected Greece and contributed to its woes by insisting on crushing budget cuts.

"Her visit to Athens is primarily about political positioning, and the opportunity to clarify her position on Greece," said Alex White, an analyst at J.P. Morgan.

RISK OF VIOLENCE

Teachers, doctors and other public employees stopped work on Tuesday in a gesture of protest, while trade unions and opposition political parties took to the streets, risking confrontation with police.

Demonstrations in Athens have a habit of turning violent, hijacked by radicals armed with petrol bombs and rocks ripped from the streets.

Germany