The U.S. government last week said that it believed "with varying degrees of confidence" that forces loyal to Syrian President Bashar Assad used sarin, a, nerve gas, on civilians. U.S. President Barack Obama has said that the use of chemical weapons in Syria would be a "red line" that could force action by the United States.
Lavrov said Syria's adversaries may be using the weapons claim as an excuse to take further action to topple the Assad regime.
"I think it is unacceptable to use it, to speculate on (the use of chemical weapons) for geopolitical purposes," he was quoted by state-owned news agency RIA Novosti as saying.
Senate Armed Services Committee member Lindsey Graham, R-S.C., told the CBS News program "Face the Nation" last weekend that "we need to get involved" in the Syrian crisis.
Syria asked for an investigation into claims that anti-government forces used chemical weapons in Aleppo in mid-March.
Syria's state-run news agency SANA reported the government balked after it suspected the United Nations was trying to broaden the scope of its investigation, however.
Lavrov last week warned of a repeat of the "Iraq scenario." Inspectors were unable to verify U.S. claims made before the 2003 invasion that Saddam Hussein was harboring weapons of mass destruction.
Obama said Friday he hadn't seen "strong evidence" that chemical weapons were used in Syria.