Syria has crossed a "red line" with its use of chemical weapons, including the nerve agent sarin gas, against rebels, a move that is prompting the United States to increase the "scale and scope" of its support for the opposition, the White House said Thursday. The acknowledgment is the first time President Barack Obama's administration has definitively said what it has long suspected -- that President Bashar al-Assad's forces have used chemical weapons in the ongoing civil war. "The intelligence community estimates that 100 to 150 people have died from detected chemical weapons attacks in Syria to date; however, casualty data is likely incomplete," Ben Rhodes, the deputy national security adviser for strategic communications, said in a statement released by the White House.
@highlight
The White House says it plans to share the findings with Congress and U.S. allies
@highlight
Sen. John McCain says the rebels need anti-tank and anti-aircraft weapons
@highlight
Between 100 to 150 people are believed to have died in Sarin gas attacks, the White House says
@highlight
The United States plans to step up its military support of the rebels, the White House says
The administration believes that al-Assad's government maintains control of the chemical weapons and that there is "no reliable, corroborated reporting to indicate that the opposition in Syria has acquired or used chemical weapons," @placeholder statement said.