ATHENS (Reuters) - Debt-stricken Greece appealed to its European partners and the IMF for emergency loans on Friday, yielding to overwhelming market pressure to start the first financial rescue of a member of the euro zone.

Prime Minister George Papandreou asked to tap the 45 billion euro ($60.5 billion) package after investors feared a default and pushed borrowing costs to record levels, undermining Athens’ efforts to cut its 300 billion euro debt pile.

“It is a national and imperative need to officially ask our partners in the EU for the activation of the support mechanism we jointly created,” Papandreou said in a statement broadcast live from the remote, tiny Aegean island of Kastellorizo.

“The time that was not granted to us by the markets will be given to us by the support of the euro zone.”

European markets rallied on the announcement but fell back as investors said the long-awaited bailout, which could be the largest multilateral rescue of a country ever tried, would bring only short-term relief.

There were concerns it could force harsher austerity on Greece, deepening its recession, and that it would set a precedent for other euro zone underperformers.

Greek riot police fired teargas on Friday at leftist protesters marching through central Athens against austerity measures, police said.

The euro was up 0.8 percent on the day at $1.3390.

The Greek crisis has hit confidence in the single currency which is shared by 16 of the 27 EU member states. There are fears problems could spread to weaker euro-zone economies like Portugal and Spain and fuel skepticism in some quarters about the euro’s long-term survival.

“On the one hand it could be perceived a relief that Greece is taking the financial help but it does not address the systemic risk and begs the question as to whether countries like Spain may look for the same rescue package in the near future,” said Simon Brown, CEO of financial analysts Prospreads in London, forecasting further euro weakness.

The premium investors demand to buy Greek 10-year government bonds rather than euro zone benchmark Bunds tightened to 525 basis points, versus 611 on Thursday, before rebounding back to 570.

Torn between punishing global market forces and Greek workers protesting at painful austerity measures, Papandreou’s socialist government hesitated over pressing the “help” button, tempting investors to bet against its debt.

The last straw came on Thursday when the European Commission revealed that Greece’s 2009 public deficit was even higher than feared at 13.6 percent of gross domestic product, raising the bar for this year’s drastic cut. That drove Greek bond yields to 12-year highs, making borrowing prohibitive.

The decision to invoke the aid mechanism followed a marathon seven-hour cabinet meeting, at which some ministers voiced fears of still tougher austerity conditions, Greek media reported.

“This certainly does not mark the end of the crisis, there’s still much further to go,” said Ben May, European economist at Capital Economics. “They’ve still got the medium-term problems of getting their public finances in order, and obviously the issue of competitiveness.”

TIMING IN FOCUS

Athens continued talks with the Commission, the European Central Bank and the International Monetary Fund on Friday on a three-year fiscal program including the aid package. Time is pressing, with an 8.5 billion euro bond due to mature on May 19.

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Finance Minister George Papaconstantinou said he expected the first tranche of aid to be disbursed before that deadline.

France said it hoped to approve its portion between May 3-6. German Finance Minister Wolfgang Schaeuble, who will meet top lawmakers on Monday to discuss fast-track approval for loans to Greece, said Berlin would make its contribution if the EU, the ECB and the IMF agree Athens needs help. [nBEB004452]

The United States, which has a veto over IMF decisions, supported Greece’s decision to ask for the activation of the aid package, the White House said. [nN23188357]

Economists say a rescue is likely to entail further European and IMF aid in 2011 and 2012, and some forecast Greece will have to restructure its debt.

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French and German banks are among the biggest holders of Greek bonds. Germany’s deputy finance minister on Friday said speculation about debt restructuring was unfounded.

It could take a week for the Commission and ECB to decide if Greece’s request is valid and for euro zone finance ministers to then take a formal decision, the Commission said.

“Everything is going to be done in such a way that the mechanism can be triggered as soon as (necessary) and as is necessary for Greece,” spokesman Amadeu Altafaj said.

He said interest on the loans -- expected to be around 5 percent from euro zone states -- would be in line with a formula worked out by euro zone finance ministers earlier this month. Because the date of the disbursement was not known yet, it was impossible to say now what the exact level would be.

Greece has said the Commission could potentially offer a bridge loan to fill a gap if the aid were not approved in time to cover its funding needs.

The timing could hardly be worse for German Chancellor Angela Merkel. She faces strong public opposition to aid for Greece ahead of a key regional election on May 9 in which the center-right government’s upper house majority is at stake.

Germany is Europe’s largest economy and would be the biggest contributor to a bailout. Merkel has had to drop her initial resistance to financial assistance and back down on demanding market rates on loans.

After a telephone call with Papandreou on Friday, she told reporters: “I’m absolutely in agreement with (Foreign Minister) Guido Westerwelle that the stability of our currency has priority, on the other hand we also agree that the savings efforts of Greece have to be absolutely credible.” [nLDE63M1T0]

STICKING-PLASTER

Another question is whether the 30 billion euros pledged by euro zone states and 10-15 billion from the IMF will cover the 39 billion euros in debt Greece has coming due in the next 12 months, plus other costs forecast in the 2010 budget deficit.

“In the longer-term, it’s just a sticking plaster over the situation,” said Daragh Maher, deputy head of forex strategy at Credit Agricole CIB. “The situation remains highly uncertain.”

Papandreou won an election last year pledging to tax the rich and help the poor. He has come under increasing pressure since his government announced Greece’s 2009 budget gap was twice previous estimates and four times the EU ceiling.

The main Greek public sector union brought nurses, teachers and other public service workers onto the streets of Athens against the government’s austerity measures. It vowed another 24-hour strike in early May.

A poll showed on Friday support for Papandreou, while still high, was falling and a majority feared the bailout would hit living standards. In Athens, many said the deal was inevitable, but public sector worker Sofia Hatzaki was angry.

“I hit the roof when I heard,” she said. “I want to scream. This means more austerity measures are coming and recovery is very far away.”