British Prime Minister Theresa May has ordered British submarines to move within missile range of Syria in readiness for strikes against the Syrian military that could begin as early as Thursday night, the Daily Telegraph newspaper said.
- Dozens killed in Syria chemical attack
- Trump to make decision on Syria following suspected chemical weapons attack
Ms May has not reached a final decision on whether Britain would join any strikes by the United States and France in response to a suspected chemical attack, but wants to be able to act swiftly, the newspaper said.
It quoted government sources as saying Britain was "doing everything necessary" to be able to fire Tomahawk cruise missiles from submarines against military targets in Syria.
Missiles "will be coming" - Trump
US President Donald Trump warned Russia on Wednesday of imminent military action in Syria over the suspected attack, declaring that missiles "will be coming" and lambasting Moscow for standing by Syrian President Bashar al-Assad.
The White House pushed back against suggestions that Mr Trump had broadcast his plans for military strikes via Twitter, saying he had not laid out a timetable for action, that all options were still on the table and he was assessing how to respond.
Mr Trump's tweet was reacting to a warning from Russia that any US missiles fired at Syria over the deadly assault on the rebel enclave of Douma near Damascus would be shot down and the launch sites targeted.
His comments raised the prospect of direct conflict over Syria for the first time between the two world powers backing opposing sides in the seven-year-old civil war, which has aggravated instability across the Middle East.
"Russia vows to shoot down any and all missiles fired at Syria. Get ready Russia, because they will be coming, nice and new and 'smart!'," Mr Trump wrote on Twitter.
"You shouldn't be partners with a Gas Killing Animal who kills his people and enjoys it!" Mr Trump tweeted, referring to Moscow's alliance with Assad.
"Smart missiles should fly towards terrorists, not towards the lawful government," Russia's foreign ministry said in response.
Damascus and Moscow have denied any responsibility and say the incident is bogus.