The Pentagon chief on Thursday called on Moscow to pursue a political solution to help put an end to the four-and-a-half-year conflict in the Arab nation.
Carter said if Russia were to fight ISIL terrorists, and not just attack opponents of Syrian President Bashar al-Assad, Washington and Moscow might work together.
"On a course like that, it is possible that we could find areas of cooperation," Carter told reporters.
"But if it's a matter of pouring gasoline on the fire on the civil war in Syria, that is certainly not productive," he added.
US officials claim that Russia is engaged in a military build-up in the Arab nation.
They say Moscow has recently sent hundreds of troops, as well as fighter jets, artillery and other military hardware to an airport in Syria’s western province of Latakia.
Washington says that Moscow is seeking to establish a military outpost in Syria to help the government in its fight against ISIL terrorists. US officials also said the deployment raises the possibility of air combat missions in Syrian airspace.
On Wednesday, US Secretary of State John Kerry warned that Moscow’s support for the Syrian government could lead to a confrontation between American forces and Russian troops in the Arab country.
"These actions could provoke a further escalation of the conflict and lead to the loss of more innocent lives, increasing the flow of refugees and risking a confrontation with the anti-ISIL coalition operating in Syria," Kerry said, referring to the US-led group said to be fighting against ISIL terrorists in Syria and Iraq.
Kerry told the Italian newspaper La Stampa that he had told Russian Foreign Minister Sergei Lavrov that Washington was very concerned by Moscow’s military support for the government of President Bashar al-Assad.
Syria has been gripped by deadly violence since March 2011. The United States and its regional allies - especially Qatar, Saudi Arabia and Turkey - have been supporting the militants operating inside Syria since the beginning of the crisis; Press TV reported.