British Foreign Secretary William Hague warned Saturday that the Syrian government might use chemical weapons against the rebels fighting the Assad regime, as Damascus reiterated that it would never resort to such tactics against civilians.

AFP quoted Hague as saying that intelligence reports pointed to evidence that Damascus might put its chemical weapons stockpiles to use against insurgents trying to overturn Syrian President Bashar Assad.

“We are extremely concerned about the stockpiles of chemical and biological weapons, and we are also concerned about evidence during the last couple of weeks that the regime could use them,” Hague said on the sidelines of a regional security conference in Manama, the capital of Bahrain.

He added that the British government’s concern that the weapons would be used by Assad or others was shared by Washington.

“We have contingency plans concerning chemical weapons but will not disclose them,” he was quoted as saying.

On Friday, Syrian opposition leader George Sabra urged the international community to act against Assad’s regime before it inflicts a chemical weapons disaster on its people.

Assad would not “hesitate to commit such atrocities as he approaches his inevitable end unless he faces firm and unequivocal international opposition,” Sabra said.

“We ask the countries of the world to act before disaster hits, not after,” said the Syrian National Council president, calling for actions, not words.

Earlier on Friday, UN Secretary-General Ban Ki-moon renewed his call to Syria not to use chemical weapons, saying their use would amount to an “outrageous crime in the name of humanity.”

The regime has insisted it would never use chemical weapons, of which it is believed to have one of the world’s largest stocks, against the Syrian people. NBC reported on Thursday that forces loyal to Assad had already locked and loaded precursory chemicals for the deadly nerve agent sarin into bombs which could be dropped from planes.

Ban on Friday also called for an end to the violence to allow a “political dialogue” and urged the UN Security Council to “stand united and act decisively” to end the crisis.

The Associated Press contributed to this report.