The British defence minister has appealed for political consensus while laying the groundwork for air strikes on Islamic State (IS) targets in Syria, saying the terrorists needed to be targeted "at source".
Defence Secretary Michael Fallon said no action would be taken without a House of Commons vote and a "consensus" among British MPs.
The UK does not need the backing of MPs to launch raids but Fallon has said they will have the final say.
Labour has indicated it would not oppose military action in Syria as it did in 2013.
Acting leader Harriet Harman said Islamic State had to be "stopped" and Labour would look "very seriously" at any proposals brought forward by the government.
The House of Commons call came as it was confirmed that 30 of the 38 tourists killed on the beach in Sousse on June 26 were British.
Fallon told MPs a "full spectrum response" was needed to deal with IS at its source.
"We will not bring a motion to this house on which there is not some consensus. Our position therefore remains that we would return to this house before conducting air strikes in Syria," he said.
Prime Minister David Cameron later said IS posed "an existential threat" to the West, and its members in Iraq and Syria were plotting "terrible attacks" on British soil.
Downing Street said Cameron believed MPs should be thinking about whether UK forces should be doing more to tackle IS.
Cameron had been defeated in the Commons in 2013 when Tory rebels joined forces with Labour to oppose air strikes on Syrian government targets designed to deter the use of chemical weapons.
The 2013 vote focused on Syrian President Bashar al-Assad, and not IS militants.
Parliament had also approved UK bombing of militant positions in Iraq last year. However, MPs were not asked at the time to authorise strikes across the border in Syria.
