Syrian President Bashar al-Assad ordered a national referendum next week on a new constitution that could break his family's four-decade grip on power, but the move was barely heeded by Syria's opposition as the government widened its assault on restive cities.

The draft constitution, a precursor to promised multi-party parliamentary elections, is a pillar of long-touted political reforms that President Assad has begun to push through as he faced unprecedented protests against his nearly 12-year rule. It would be historic for a country dominated by Baath Party rule since 1963 and the Assad family dynasty since 1970.

But as Syria's military widened an offensive against opposition strongholds to include new cities Wednesday, activists reiterated that the window for reforms had shut and that Mr. Assad must step down.

A resident of Homs reached by telephone said he hadn't yet heard of the constitutional referendum, which Syria's state news agency said is set for Feb. 26. "It shows this regime lives in a different world, offering we go to a ballot box under bombs," he said.

In Washington, White House Press Secretary Jay Carney said the move is "laughable" and "makes a mockery" of the uprising.