US President Donald Trump has cast doubt over the timing of his threatened strike on Syria in response to a reported poison gas attack on a rebel enclave.
"Never said when an attack on Syria would take place. Could be very soon or not so soon at all!" said Mr Trump in his latest early morning tweet on Thursday.
That appeared a day after he tweeted that missiles "will be coming" after the April 7 chemical weapons attack alleged to have killed dozens of people, and lambasted Moscow for standing by Syrian President Bashar al-Assad.
- Trump warns Russia that missiles are 'coming, nice new and smart'
- UK sends submarines to Syria, ready to strike within 24 hours
Prime Minister Theresa May prepared to convene a special cabinet meeting to weigh whether Britain should join the United States and France in a possible military action.
Ms May recalled ministers from their Easter holiday to debate action over what she has cast as a barbaric poison gas attack by Syrian government forces on civilians in the formerly rebel-controlled town of Douma, just east of the capital Damascus.
There were signs, though, of a global effort to head off a dangerous conflict pitting Russia against the West. The Kremlin said a crisis communications link with the United States, created to avoid an accidental clash over Syria, was in use.
"The situation in Syria is horrific, the use of chemical weapons is something the world has to prevent," Britain's Brexit Minister David Davis said on Thursday morning.
"But also it's a very, very delicate circumstance and we've got to make this judgment on a very careful, very deliberate, very well thought-through basis."
Western powers on the fence
French President Emmanuel Macron said he would decide whether to strike Syrian government targets after the reported attack by internationally banned chemical munitions in Douma once all the necessary information had been gathered.
"We will need to take decisions in due course, when we judge it most useful and effective," Mr Macron said.
Germany will not join any military strikes, but supports Western efforts to show chemical weapons use is unacceptable, Chancellor Angela Merkel says.
"Germany will not take part in possible - there have not been any decisions yet, I want to stress that - military action," she said after meeting Danish Prime Minister Lars Lokke Rasmussen in Berlin on Thursday.
"But we support everything that is being done to show that the use of chemical weapons is not acceptable," she added.
At the eye of the storm, Mr Assad said any Western action "will contribute nothing but an increase in instability in the region, threatening international peace and security", Syrian state television reported.
Syria's military has repositioned some air assets to avoid fallout from possible missile strikes, US officials told Reuters on Wednesday.
Syria's attempt to shelter aircraft, perhaps by locating them alongside Russian military hardware that Washington might be reluctant to hit, could limit damage that the US and its allies might be able to inflict on Assad's military.
US Defence Secretary Jim Mattis, striking a cautious tone after Mr Trump's threat of missile strikes, said on Wednesday the United States was still assessing intelligence about the suspected toxic gas attack.
Both Syria and Russia have said reports of the attack were fabricated by rebels and rescue workers in Douma and have accused the United States of seeking to use it as a pretext to attack the government.
Any US strike would probably involve the navy, given the risk to aircraft from Russian and Syrian air defences. A US guided-missile destroyer, the USS Donald Cook, is in the Mediterranean.
Ms 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, London's Daily Telegraph newspaper said on Wednesday.