The UN Security Council has failed to agree on a statement condemning Syria's deadly crackdown on peaceful protesters.
Envoys attending a special open meeting on Syria in New York on Wednesday said Russia, China and Lebanon opposed the wording of a draft statement distributed by European nations.
France called for "strong measures" if Bashar al-Assad, the Syrian president, rejects appeals to end violence which has killed hundreds.
The US said Assad must "change course now and heed the calls of his own people" for change.
"A real threat to regional security could come from outside interference. Such approaches lead to a never ending circle of violence"
Alexander Pankin, Russian deputy UN envoy
Russia, after blocking a Security Council statement condemning the violence, however insisted that the Syrian crackdown did not amount to a threat to international peace and security, grounds that would justify international action.
"A real threat to regional security could come from outside interference," Alexander Pankin, the Russian deputy UN ambassador, told the council.
"Such approaches lead to a never ending circle of violence" and could set off civil war.
Bashar Ja'afari, the Syrian ambassador to the UN, welcomed the Security Council's inaction, saying his government was carrying out an investigation into the violence and that there was no need for a UN commission.
Al Jazeera's Kristin Saloomey, reporting from the UN headquarters, said any hope for Security Council action is "dead" for the moment.
"The council was not able to agree on even the most basic form of the statement calling for calm and calling for an investigation."
She said Russia offered the strongest opposition to the move, saying they were concerned about violence in Syria, but on both sides.
"In the end there were isolated statements of concern from various countries, but no unified action by the council."
China and India called for political dialogue and peaceful resolution of the crisis, with no mention of condemnation.
Nawaf Salam, the Lebanese envoy, said his country shared a special relationship with Syria, and that "the hearts and minds" of the Lebanese people are with the Syrians, and are supporting Assad's lifting of the state of emergency and reforms.
The Syrian violence has sparked global criticism in recent days.
France, Britain, Germany and Portugal circulated a draft media statement on Monday calling for the 15-member Security Council to condemn the violence.
But during consultations on Wednesday afternoon, several members opposed the move. The UN the Security Council then moved into open session to hear a briefing from the UN political chief and statements from council members.
B. Lynn Pascoe, the UN under-secretary general for political affairs, told envoys that protesters who began with demands for greater freedom "are now increasingly calling for the downfall of the regime, echoing slogans that have been heard elsewhere in the region".
He told envoys that "a review of the reports of media, international human rights groups, UN agencies and diplomatic missions confirm that the overwhelming majority of protests have been peaceful and unarmed".
"However, there have been credible reports of a very few instances where protesters have used force, resulting in the deaths of members of the security forces."
Highlighted the "increasingly violent repression" and "siege-like conditions" in Deraa and other cities, Pascoe estimated the number of deaths to be between 350 and 400 people since mid-March.
Rights groups say at least 450 people have been killed.
International pressure on Assad began to mount on Wednesday, with European governments urging Syria to end the violence.
"If nothing positive happens, France, with others, will study a series of options aiming to increase pressure on the Syrian regime so that it stops the repression and engages on the path to reform," Gerard Araud, the French ambassador to the UN, said.
France, Britain, Germany, Italy and Spain told Syrian ambassadors in a co-ordinated effort that they condemned the recent crackdown and that Assad must change his ways, according to France's foreign ministry.
The ministry said France expressed its "firm condemnation of the escalation of the repression by Syrian authorities against the population" and called on Syria to respect its international obligations on human rights.
European Union governments will discuss the possibility of imposing sanctions against Syria on Friday, with various measures being explored, a spokesman for Catherine Ashton, the EU foreign policy chief, said.
"All options are on the table," he said.
The US is separately considering targeted sanctions, the country's ambassador has told the UN.
In a related development, the UN's main human-rights body, the Human Rights Council in Geneva, has agreed to hold a special session on Syria on Friday.
The meeting was requested by the US and endorsed by 16 member states including Britain, France, and Japan.
No Arab countries were among those requesting the session, which requires endorsement by one-third of the forum's membership to convene.
Emergency sessions in recent months have launched investigations into alleged human rights violations in Libya and Ivory Coast.
Ban Ki-moon, the UN secretary-general, has called for an independent inquiry into the deaths of people he described as peaceful demonstrators.
Syria's UN ambassador has said the country is perfectly capable of conducting its own transparent inquiry into the deaths.
Ja'afari said on Tuesday Assad had instructed the government "to establish a national commission of inquiry and investigation about all the casualties among civilians" and the envoy pledged "full transparency".
"We have nothing to hide," he said.
"We regret what's going on, but you should also acknowledge the fact that this unrest and riots, in some of their aspects, have hidden agendas," he said.
Ja'afari accused some foreign governments of trying to destabilise Syria.
His comments came as Syrian opposition figures warned that their "massive grassroots revolution" would break the regime unless Assad leads a transition to democracy.
The statement on Wednesday from an umbrella group of opposition activists in Syria and abroad, called the National Initiative for Change, said a democratic transition would "safeguard the nation from falling into a period of violence, chaos and civil war".
"If the Syrian president does not wish to be recorded in history as a leader of this transition period, there is no alternative left for Syrians except to move forward along the same path as did the Tunisians, Egyptians and Libyans before them," the statement said.
The opposition in Syria is getting more organised as anti-government protests gain strength, but it is still fragmented.