There’s only one opposition group in Syria, the Muslim Brotherhood.

(The Hill) — President Obama should “state unequivocally” that Syrian leader Bashar al Assad should step down from power, Sens. John McCain (R-Ariz.), Lindsey Graham (R-S.C.) and Joe Lieberman (I-Conn.) said Thursday.

The trio ramped up pressure on Obama to take a stronger stance against the Assad regime, which has violently cracked down on anti-government protesters demanding reforms.

“We urge President Obama to state unequivocally — as he did in the case of Qaddafi and Mubarak — that it is time for Assad to go,” the senators said in a statement referring to the leaders of Libya and Egypt. “The President should take tangible diplomatic and economic measures to isolate and pressure the Assad regime, including through targeted sanctions against Assad himself and other regime officials who are responsible for gross human rights abuses.”