"While the Syrian army is on the offensive, saying that it is the Syrian government that used chemical weapons is utter nonsense," Putin told journalists in Vladivostok, according to Russia's Interfax news agency.
He urged the United States to present its evidence to the UN Security Council and cautioned President Obama about the consequences of getting involved.
"I would like to address Obama as a Nobel Peace Prize laureate: before using force in Syria, it would be good to think about future casualties," he said.
On Friday, the Obama administration published evidence it says proves the Syrian military was responsible for the attack near Damascus two weeks ago.
Secretary of State John Kerry said the attack killed 1,492 people, including hundreds of children.
On Saturday, the US Ambassador in Moscow Michael McFaul presented that evidence to Russia's Deputy Foreign Minister Sergei Rybakov.
According to the Russian Foreign Ministry, Rybakov urged the United States not to use the incident to justify increasing military pressure on the Assad government.
He said Russia would regard Western intervention as "a flagrant violation of international law."
Putin said he thinks the chemical attack was a "provocation" by Assad's opponents who wished to draw the United States and other powers into the conflict.
"Common sense speaks for itself: the Syrian government forces are on the offensive, and they have encircled insurgents in some regions, and it would be utter stupidity to give up a trump card to those who have been regularly calling for military intervention. It defies any logic, especially on the day when UN monitors came there," he told reporters.
Putin said he believes Western intervention is only aimed at helping the rebels, which he suggested have recently lost ground to government forces.
"There is only one solution: to strike for them. If this happens, this would be extremely sad," Putin said.
Putin said he thinks the G20 summit, which Russia will host next week in St Petersburg, "is a good forum for discussing the Syria problem, so why not take advantage of this?"
He also praised the British vote not to join in any strike, saying it shows there are people with "common sense there."
"The British parliament's decision on Syria is an absolute surprise to me. It shows that there are people guided by common sense there," he said.
Putin also said Russia was willing to take part in any international efforts to prevent the use of chemical weapons.