LONDON: Syrian President Bashar al-Assad's intransigence and brutality mean there is a serious risk violence in Syria will worsen, and if so the international community must "step up" its response, British Foreign Secretary William Hague said on Thursday.

"President Assad's speech last week urged the Syrian people to unite in a war against his opponents. Given the regime's intransigence and brutality, there is a serious risk that the violence will indeed worsen in the coming months," Hague told parliament.

"If that happens the international community's response will have to be stepped up. So we will not rule out options to save lives and protect civilians," he added.