European leaders have reached a "three-pronged" agreement which they say is vital to resolving the region's massive debt crisis.

欧盟领导人为解决此次严重的债务危机达成了“三方面”协议。

After marathon talks in Brussels, the leaders said private banks holding Greek debt had accepted a loss of 50%.

Banks must also raise more capital to protect them against losses resulting from any future government defaults.

The deal also approved a mechanism¹ to boost the eurozone's main bailout fund to 1tr euros (£880bn; $1.4tn).

The framework for the new fund is to be put in place in November.

The BBC's Chris Morris in Brussels says the deal is not as ambitious（野心勃勃的） as some had hoped but as much as could be achieved.

The announcement helped lift the euro, with investors² reacting positively³ to the outlook for the region's growth and single currency.

"The eurozone has adopted a credible⁴ and ambitious response to the debt crisis," a visibly tired French President Nicolas Sarkozy said at a news conference early in the morning in the Belgian capital.

Fears about the state of the eurozone's finances and the threat of a break-up of the single European currency have been stalking markets for months.

Critics have accused policymakers of not doing enough to resolve the issues, contributing further to problems and fuelling uncertainty⁵.

'Marathon not sprint⁶'

Leaders of the 17 eurozone nations had been in meetings since Wednesday trying to hammer out a deal to help Greece put its national finances in order and underpin⁷（巩固，支持） other European economies such as Italy.

Speaking after the deal was agreed, Mr Sarkozy said that "the complexity⁸ of the files, the necessity to get everybody to agree, means that we have been negotiating for long hours".

He said he believed the result would be a relief for "the whole world", which had been expecting a strong decision from the summit.

Because banks have agreed to shoulder losses on Greek bonds, the country's burden has been reduced, cutting its debt down to 120% of its gross domestic product by 2020.

Greek Prime Minister George Papandreou hailed the deal, saying: "We can claim that a new day has come for Greece, and not only for Greece but also for Europe."

The eurozone leaders also said the firepower of the main euro bailout fund - known as the European Financial Stability Facility (EFSF) - would be boosted from the current 440bn euros to 1tn euros.

Bank recapitalisation - the third key element of the package - was agreed earlier.

The banks would now be required to raise about 106bn euros in new capital by June 2012.

It is hoped that this would help shield them against losses resulting from any government defaults and protect larger economies - like Italy and Spain - from the market turmoil⁹.

"The package that we have agreed tonight, a comprehensive package, confirms that Europe will do what it takes to safeguard financial stability," said the President of the European Commission, Jose Manuel Barroso.