UNITED NATIONS (AFP) - - The UN Security Council failed yet again to agree on a call for an immediate truce in the worsening fighting in Georgia's breakaway South Ossetia enclave but agreed to make another attempt Saturday.

At Georgia's request, the 15-member council held a second emergency meeting to try to defuse mounting tension after Russian tanks and troops surged into South Ossetia to repel a Georgian offensive to reclaim the breakaway region amid fighting said to have left hundreds dead.

"Some members of the council need more time ...This negotiation has not come to a halt tonight and will be resumed tomorrow (Saturday)," Belgium's UN envoy Jan Grauls, the council chair this month, said as he emerged from hours of closed-door consultations.

"The expectation around the world is for a ceasefire, for an end to use of (Russian) aerial bombing, missile attacks, use of combat forces,� US Ambassador Zalmay Khalilzad told reporters. "The time has come to cease these attacks."

But he said that his Russian counterpart Vitaly Churkin also insisted on "the restoration of the status quo ante" that prevailed before Thursday's Georgian offensive .

Diplomats said a Belgian-drafted compromise statement also urges the warring sides to "show restraint and to refrain from any further acts of violence or force," calls for respect by the parties of past accords and for the provision of humanitarian aid to the victims.

As he did during an overnight debate that also proved inconclusive, Churkin again insisted on the need for Tbilisi to agree to a formal renunciation of the use of force by either side.

Tbilisi was entirely to blame for the escalation and was continuing "its treacherous attacks" on South Ossetia "with the connivance of a number of Security Council members," the Russian envoy said.

"A humanitarian catastrophe is in the offing," he added as he accused Georgia of "gross violations of humanitarian law," including reports of ethnic cleansing and attacks on civilians.

Earlier Friday, Russia's defense ministry said more than 10 of its troops deployed in South Ossetia had been killed amid the Georgian offensive in the breakaway region, according to Russian news agencies.

"We will not allow to go unpunished the deaths of our compatriots," Churkin warned as he said Moscow was rushing relief to thousands of South Ossetians fleeing the fighting.

"Historically Russia was and will remain the guarantor of the security of the people of the Caucasus," he added.

Britain's deputy ambassador Karen Pierce made clear that "humanitarian assistance cannot be used as a pretext for the presence of non-Georgian troops."

Georgian Ambassador Irakli Alasania said his country was acting in "self-defense" and charged that Russia "started a full-scale military invasion" of his country and had even sent strategic bombers to strike targets across Georgia.

He also accused Moscow of "openly challenging the international community" and demanded an immediate end to its "criminal acts."

French Foreign Minister Bernard Kouchner, whose country currently holds the rotating EU presidency, is "in contact with all the protagonists in the crisis" to try to obtain a ceasefire, his ministry said Friday.

Khalilzad urged "the parties to show the utmost restraint and refrain from actions that would further inflame the situation."

The Security Council had met for several hours overnight at Moscow's request but failed to agree on a Russian statement that would have called on Georgian troops and their separatist foes to renounce the use of force.

Meanwhile the European Union, France, the United States, Britain and NATO pressed for an immediate end to the violence in South Ossetia.

South Ossetia broke from Georgia in the early 1990s and has since been a constant source of friction between Tbilisi and Moscow.

The Tbilisi government accuses Russia of wanting to take over the province, and launched its new assault in an apparent bid to stamp its authority on South Ossetia.

In recent months, Moscow and Tbilisi have sparred repeatedly over South Ossetia and another breakaway Georgian region, Abkhazia.