The U.S. has determined that the government of President Bashar al-Assad is using chemical weapons -- including the nerve agent sarin -- on civilians. In doing so, Syria has crossed a "red line," the White House said in a statement issued on Thursday. According to CNN, the U.S. will now be increasing its “scale and scope” for supporting opposition to al-Assad's government.

For some time, President Obama’s administration has suspected that al-Assad’s military was using chemical weapons. Now the U.S. is acknowledging the attacks, and deputy national security adviser for strategic communications Ben Rhodes has said that more than 100 Syrians have died because of chemical weapons used by government forces.

"The intelligence community estimates that 100 to 150 people have died from detected chemical weapons attacks in Syria to date," Rhodes said in the White House statement. "However, casualty data is likely incomplete."

He added that "while the lethality of these attacks make up only a small portion of the catastrophic loss of life in Syria, which now stands at more than 90,000 deaths, the use of chemical weapons violates international norms and crosses clear red lines that have existed within the international community for decades."

The administration seems to be leaning toward supporting the rebels, but didn’t directly say it would be providing the opposition with firearms.

"Put simply, the Assad regime should know that its actions have led us to increase the scope and scale of assistance that we provide to the opposition, including direct support to the [rebel Supreme Military Council]. These efforts will increase going forward," Rhodes' statement said.

CNN wrote that during a conference call, Rhodes told reporters President Obama wasn’t sure if a no-fly zone in Syria would be instituted. Al-Assad has claimed that the rebels were the ones using chemical weapons, even telling this to the United Nations. But when U.N. inspectors wanted to enter the country to validate the claims, he would not allow it, according to news reports.

As a result, the Obama administration believes it’s al-Assad’s forces who are in 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," Rhodes' statement noted.