President Vladimir Putin has challenged the US to present to the UN evidence that Syria attacked rebels with chemical weapons near Damascus.
The Russian president said it would be “utter nonsense” for Syria’s government to provoke opponents with such attacks.
President Barack Obama says he is considering military action against Syria after intelligence reports that 1,429 people were killed on August 21.
UN weapons inspectors have left Syria after gathering evidence for four days.
They are taking their samples to the Organization for the Prevention of Chemical Weapons, in The Hague.
The samples are thought to include soil, swabs from munitions, blood and hair from the victims and, experts say, possibly even flesh from dead bodies.
The US says hundreds of children were among those killed in the suspected chemical weapons attacks, which the US says was carried out by the Syrian government.
Syria said the US claim was “full of lies”, blaming rebels for the attacks.
President Barack Obama said on Friday the US was planning a “limited, narrow” military response that would not involve “boots on the ground”.
The inspectors’ departure from Syria removes both a practical and a political obstacle to the launch of US-led military action, correspondents say.
Syrian people are worried and are making preparations.
Vladimir Putin urged Barack Obama, as a Nobel Peace Prize laureate, to think about future victims in Syria before using force
They do not know what Barack Obama means by a limited attack and what consequences it will have for them.
Speaking to journalists in the Russian far-eastern city of Vladivostok, Vladimir Putin urged Barack Obama – as a Nobel Peace Prize laureate – to think about future victims in Syria before using force.
The Russian president said it was ridiculous to suggest the Syrian government was to blame for the attack.
“Syrian government troops are on the offensive and have surrounded the opposition in several regions,” Vladimir Putin said.
“In these conditions, to give a trump card to those who are calling for a military intervention is utter nonsense.”
“So I’m convinced that is nothing more than a provocation by those who want to drag other countries into the Syrian conflict.”
Vladimir Putin said that the US failure to present evidence to the international community was “simply disrespectful”.
“If there is evidence it should be shown. If it is not shown, then there isn’t any,” he said.
Russia – a key ally of Syria – has previously warned that “any unilateral military action bypassing the UN Security Council” would be a “direct violation of international law”.
Moscow, along with China, has vetoed two previous draft resolutions on Syria.
Vladimir Putin also expressed surprise at a vote in the British parliament on Thursday ruling out participation in military action.
“I will be honest: this was completely unexpected for me,” he said.
“This shows that in Great Britain, even if it is the USA’s main geopolitical ally in the world… there are people who are guided by national interests and common sense, and value their sovereignty.”
Meanwhile in France – seen as the main US ally since the UK vote – an opinion poll suggested that 64% opposed the use of force.
Neither France nor the US needs parliamentary approval for military action.
Syrian President Bashar al-Assad has said his country will defend itself against any Western “aggression”.
The Algerian military operation to free hostages being held by Islamist militants at a desert gas plant is now over, state news agency APS reports.
State TV said four foreign hostages were killed in the operation. Others were freed, but there was no confirmation of how many survived.
AFP news agency quoted officials as saying the army had not secured the whole site, which was being searched.
Al-Qaeda-linked fighters occupied the facility near In Amenas on Wednesday.
Reports suggest the facility is still being searched.
During the Algerian military intervention on Thursday as many as 600 Algerians and four foreign hostages – two from Scotland, one from France and one from Kenya – were freed, APS reported.
The Irish government confirmed that one of its citizens was free. Five American hostages had survived and had left the country, US officials were quoted as telling ABC News.
The Algerian military operation to free hostages being held by Islamist militants at a desert gas plant is now over
Earlier, the militants reportedly said that at least 34 hostages and 14 kidnappers died, and that seven foreign hostages had survived.
They had claimed to be holding 41 foreign nationals, believed to include British, Japanese, US and Norwegian citizens, in retaliation for French military intervention in neighboring Mali.
Some workers were reported to have been freed or to have escaped before the Algerian raid.
Algerian Communications Minister Mohamed Said Belaid said a “significant number of terrorists” were killed during the raid.
He added: “Unfortunately, we deplore some deaths and some people wounded. We don’t yet have the numbers.”
Details of how the raid unfolded were slow to emerge.
APS reported that the Algerian military, which had been surrounding the gas plant, had targeted two vehicles as they tried to escape from the site with an unknown number of people on board.
Militants told local media that Algerian forces had opened fire from the air.
Norwegian Prime Minister Jens Stoltenberg said he was told by his Algerian counterpart that Algerian authorities had tried and failed to find a solution to the stand-off on Wednesday night. “The Algerian prime minister said they felt they had no choice but to go in,” he said.
British Prime Minister David Cameron was informed that the raid was under way when he called the Algerian Prime Minister at 11.30 GMT, a spokesman said.
David Cameron, who cancelled a key speech on Europe scheduled for Friday, made it clear that he would have preferred to have been told in advance, the spokesman added.
Japan’s government protested against the raid, urging Algeria “put the highest priority on people’s lives”. The US said it was “seeking clarity” on what had happened.
Algerian Interior Minister Daho Ould Kablia said the kidnappers were Algerian and operating under orders from Mokhtar Belmokhtar, a senior commander of al-Qaeda in the Islamic Maghreb (AQIM) until late last year.
Daho Ould Kablia said they had entered Algeria from Libya, AFP reported.
Two people were killed when militants attacked the gas plant.
The Tigantourine gas facility is about 40 km (25 miles) south-west of In Amenas, which is close to the Libyan border and about 1,300km (800 miles) south-east of Algiers.
BP operates the gas field jointly with Algerian state oil company Sonatrach and Norwegian firm Statoil.