The U.N. Security Council, including Russia, agreed on Wednesday to a statement endorsing efforts by Kofi Annan to end the Syrian uprising, providing a rare moment of global unity in the face of the year-long crisis.

The statement, which threatens Syria with unspecified "further steps" if it fails to comply with a six-point peace plan drawn up by Annan, will be formally adopted in New York later in the day, diplomats said.

U.S. Secretary of State Hillary Clinton on Wednesday praised the move as a "positive step".

"To President Assad and his regime we say, along with the rest of the international community: take this path, commit to it, or face increasing pressure and isolation," Clinton told reporters after a meeting with Afghanistan's foreign minister.

Although the original Western-drafted statement had to be diluted at Russia's demand, editing out any specific ultimatums, the fact that all major powers signed up to the proposal represented a blow to President Bashar Assad, who is fighting for his survival.

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At least 8,000 people have died in the revolt, according to U.N. figures, with the violence intensifying in recent weeks as pro-government forces bombard rebel towns and villages, looking to sweep their lightly armed opponents out of their strongholds.

U.N. chief Ban Ki-moon said on Wednesday that the crisis was alarming and had "massive repercussions" for the entire world.

"We do not know how events will unfold. But we do know that we all have a responsibility to work for a resolution of this profound and extremely dangerous crisis," Ban said in a speech in the Indonesian capital Jakarta.

Syria lies in a pivotal position at the heart of a web of regional conflicts in the Middle East, comprising a mix of faiths, sects and ethnic groups, and diplomats fear the rebellion is degenerating into a full-blown civil war.

Assad's forces have chalked up a string of gains as they turned their firepower on areas held by rebels, but the fighting shows no sign of abating and analysts expect the insurgents to change their tactics and adopt guerrilla warfare.

Opposition activists said the army used tanks, artillery and anti-aircraft guns on the Damascus suburbs of Harasta and Irbin early Wednesday, which were retaken from rebels two months ago but have seen renewed insurgency in recent days.

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Elsewhere, the army fired mortars into the Khalidiya district of Homs, while artillery targeted the rebel town of Rastan, north of Homs city, in central Syria. Video also showed shelling of the ancient Apamea castle at Qalat Mudiq, near Hama.

Reports from Syria cannot be independently verified because officials have barred access to rights groups and journalists.

Russia and China have vetoed two previous U.N. draft resolutions that would have condemned Damascus and have resisted calls from Western and Arab states for Assad to stand down.

But faced by growing global outrage at the bloodshed, the two countries agreed to a so-called "presidential statement", which are generally non-binding documents that nonetheless require unanimous support in the Security Council.

Speaking after the UN agreement was reached, Britain's Foreign Secretary, William Hague, said: “I strongly welcome the Security Council’s full and unanimous support for the work of Kofi Annan as joint UN-Arab League envoy, expressed in today’s Presidential statement.

"I urge the Syrian authorities to take this chance to stop the bloodshed and show their commitment to implementing Kofi Annan’s six point plan, including by immediately pulling back the military from in and around population centers."

Reuters and msnbc.com staff contributed to this report.

IMF Managing Director Christine Lagarde, talking to Greece's Prime Minister Lucas Papademos on Monday, admitted after the Greek bailout deal was unveiled that "it's not an easy (program), it's an ambitious one."

Updated at 10 a.m. ET: BRUSSELS -- After months of tough negotiating, Europe and the International Monetary Fund sealed a deal early Tuesday to hand Greece €130 billion ($170 billion) in additional bailout loans to save it from a default that threatened the viability of the euro, undermining global economic confidence.

The early-hours agreement to avert default comes after negotiators persuaded private bondholders to take greater losses and Athens to commit to very severe austerity measures.

Ministers finalized measures to cut Greece's debt to 120.5 percent of gross domestic product by 2020, a fraction above the target, to secure its second rescue in less than two years and meet a bond repayment next month.

The eurozone and the IMF, which will be providing the money for the new bailout, hope the new program will eventually put Greece back into a position where it can survive without external support and secure its place in the euro currency union. Finance ministers from Greece and the other 16 euro countries meeting in Brussels wrangled until the early morning hours over how that could be achieved.

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On top of the new rescue loans, Athens will also ask banks and other investment funds to forgive it some €107 billion in debt, while the European Central Bank and other national central banks in the eurozone will forgo profits on their holdings.

The accord, which had been months in the making, seeks to reduce Greece's massive debts on all fronts, with both private and official creditors going beyond what they had said was possible in the past.

But the costs for Greece, in potential loss of autonomy and further strict austerity measures, were implicit from a statement from Eurogroup, which Europe's finance ministers belong to.

"The Eurogroup is fully aware of the significant efforts already made by the Greek citizens but also underlines that further major efforts by the Greek society are needed to return the economy to a sustainable growth path," the statement read. "We reiterate our commitment to provide adequate support to Greece during the life of the programme and beyond until it has regained market access, provided that Greece fully complies with the requirements and objectives of the adjustment programme."

So it was clear that Greece, which kicked off Europe's debt crisis two years ago, was at the very best starting a long and painful road to recovery. At the worst, the new program would push the country even deeper into recession and see it default on its debts further down the line.

"It's not an easy (program), it's an ambitious one," said Christine Lagarde, the head of the IMF, adding that there were significant risks that Greece's economy could not grow as much as its international creditors were hoping.

The austerity measures wrought from Greece are also widely unpopular among the population and may hold difficulties for a country which is due to hold an election in April. Further protests could test politicians' commitment to cuts to wages, pensions and jobs.

So social upheaval was a real risk, Paschos Mandravelis, a political analyst at Greece's Kathimerini newspaper, told NBC News' Andy Eckardt.

"If people in the broad middle class landscape get desperate and feel choked, there is the possibility of some kind of uprising," he said.

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And some economists say there are still questions over whether Greece can pay off even a reduced debt burden.

A return to economic growth could take as much as a decade, a prospect that brought thousands of Greeks onto the streets to protest against austerity measures Sunday. The cuts will deepen its five-year recession, hurting government revenues.

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A report prepared by experts from the European Union, European Central Bank and International Monetary Fund said Greece would need extra relief to cut its debts near to the official debt target given the worsening state of its economy.

If Athens did not follow through on economic reforms and savings to make its economy more competitive, its debt could hit 160 percent by 2020, said the report, obtained by Reuters.

"Given the risks, the Greek program may thus remain accident-prone, with questions about sustainability hanging over it," the nine-page confidential report said.

NBC News, msnbc.com, Reuters and The Associated Press contributed to this report