the use of chemical weapons is never acceptable".

The small Northern Irish political party that props up her government said May was justified in taking such action.

Stop the War, a pacifist coalition once chaired by Corbyn, has called a demonstration outside parliament in London on Monday to protest against the strikes.

The group said it "strongly condemned" the action and accused May of "sanctioning killing" at US President Donald Trump's behest.

Often when the British government decides on military action, the opposition offers its full support.

However, that has been less the case in recent years.

David Cameron, May's predecessor, lost a parliamentary vote on air strikes against Assad's forces in 2013 when 30 Conservative politicians voted against action, with many Britons wary of entering another conflict after interventions in Iraq, Afghanistan andLibya failed to bring stability to the region.

Legislators backed action in Iraq in 2014, and again in Syria in 2015, strictly limiting strikes in both countries to targets of the Islamic State of Iraq and the Levant (ISIL) group.

A BMG poll, taken before the strikes and published by the Independent newspaper on Saturday, indicated that 28 percent of Britons backed air strikes, with 36 percent opposed.