The Bashar Assad government in Syria has used chemical weapons, including the chemical agent Sarin, on its citizens during the civil war in the region, according to senators briefed behind closed doors Thursday by Secretary of State John Kerry and other national security officials.

Sens. John McCain, R-Ariz., Lindsey Graham, R-S.C., and Bob Corker, R-Tenn., told reporters they believe the presence of the chemical weapons signals that the Assad regime has crossed the so-called ‘red line’ the administration laid out previously that should dictate increased action by the U.S.

“It is clear that the Syrians have crossed the red line that the president said was a game changer, so it should change the game,” McCain said.

Reading from a letter given to senators at the briefing McCain said, “‘Our intelligence community does assess with varying degrees of confidence that the Syrian regime has used chemical weapons on a small scale in Syria specifically the chemical agent Sarin.’”

Graham said the letter said that the intelligence community has assessed with “moderate to high probability that small amounts of chemical weapons were used by the Assad regime.”

McCain said senators were not left with any indication about whether the information would change the U.S. policy on Syria.

“I think it is pretty obvious that red line has been crossed,” McCain said. “Now I hope that the administration will consider what we have been recommending now for over two years of this bloodletting and massacre and that is to provide a safe area for the opposition to operate, to establish a no-fly zone and provide weapons to the people in the resistance who we trust.”

McCain argued that jihadists are on the rise in the region.

“Everything that the non-interventionists said that would happen in Syria if we intervened, has happened,” he said. “The jihadists are on the ascendancy, there is chemical weapons being used, the massacres continue, the Russians continue to be assisting Bashar Assad and the Iranians are all in.”

“It requires the United States’ help and assistance,” McCain said. “It does not mean boots on the ground. Finally we have to have operational capability to secure these chemical weapons stocks. We do not want them to fall into the wrong hands.”