Tillerson appeared at a signing for the launch of the International Partnership Against Impunity for the Use of Chemical Weapons in Paris on Tuesday where he placed blame on Russia for Syria's use of chemical weapons against its own people.
"Whoever conducted the attacks, Russia ultimately bears responsibility for the victims in east Ghouta and countless other Syrians targeted with chemical weapons since Russia became involved in Syria," he said.
Tillerson's comments came after reports of a chemical weapons attack that hit east Ghouta, near the capital of Damascus, this week.
"The recent attacks in east Ghouta raise serious concerns that Bashar al-Assad's Syrian regime may be continuing its use of chemical weapons against its own people," Tillerson said. "Since April 2014, there has been mounting evidence that Syria continues to illicitly possess chemical weapons and use them against its own people."
He went on to say Russia is violating a 2013 agreement with the United States to eliminate Syria's chemical weapons as well as helping the Syrian government breach the Chemical Weapons Convention.
"There is simply no denying that Russia, by shielding its Syrian ally, has breached its commitments to the United States as a framework guarantor," Tillerson said.
Russia has twice vetoed resolutions for an investigative body to examine who is responsible for chemical weapons attacks in Syria and drafted a U.N. Security Council resolution calling for a new structure to investigate chemical attacks, Russia's state-runTass news agency reported.
"We want to raise above disputes and suggest a new international investigative body be set up to establish facts on the basis of scrupulous and incontestable evidence received by means of transparent and reliable methods so that the Security Council could identify those responsible for the use of poisonous agents as weapons," said Russia's permanent representative to the United Nations Vasily Nebenzya.
Tillerson called on Russia to "at a bare minimum" stop vetoing and at least abstain from future Security Council votes regarding investigations into who is responsible for the attacks in Syria.
"Over 25 like-minded countries are here today to ensure that those who use chemical weapons will be held accountable," he said. "The choice is yours. The people of East Ghouta are watching and the rest of the world is watching as well."