House Speaker John Boehner, R-Ohio, urged President Obama not to back down from his pledge that use of chemical weapons by Syrian dictator Bashar al-Assad in his fight to keep power would cross a United States red  line and prompt an American response.

“I have and will continue to support the President’s articulated red line of confirmation of the use of chemical weapons or the transfer of such weapons to terrorist groups,” Boehner said in a statement today. “At the same time, I am deeply concerned with reports that further confirmation of use may be outsourced to the United Nations.  If Assad sees any equivocation on the red line, it will embolden his regime.”

A senior White House official told reporters that the Obama team isn’t sure if Assad used the weapons. “We are continuing to do further work to establish a definitive judgment as to whether or not the red line has been crossed and to inform our decision-making about what to do next,” the official said, per The Cable. “If we reach a definitive determination that this red line has been crossed, based on credible, corroborated information, what we will be doing is consulting closely with our friends and allies and the international community more broadly, as well as the Syrian opposition, to determine what the best course of action is.”