THE momentum towards war over the suspected chemical attack in Syria appears to have stalled as Donald Trump softened his language and weapons inspectors prepared to enter Douma to make tests.

James Mattis, the US Defence Secretary, told a Congressional hearing that Washington’s two main concerns over a military strike were the protection of civilians and avoiding an escalation that got “out of control”.

He said America was “looking for the actual evidence” of a chemical attack and wanted the inspectors to arrive in Syria “probably within the week”.

But France’s Emmanuel Macron insisted his Government had “proof” that the Assad regime had carried out last Saturday’s poison gas attack on the Damascus suburb, which is said to have killed up to 75 people, including children.

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And US officials suggested blood and urine samples from the victims of Saturday’s attack showed traces of chlorine and a nerve agent.

As a pause in the heated rhetoric occurred, Moscow confirmed that a so-called “de-confliction hotline” between the US and Russia was now “active”.

The US President, who had urged Russia to “get ready” for military strikes, took to Twitter again but appeared to take a step back, noting how US missiles could be launched “very soon or not so soon at all”.

At the United Nations, Vassily Nebenzia, the Russian envoy, said Russia’s “immediate priority is to avert the danger of war”, while in Moscow the Russian foreign ministry stressed that it was “not seeking escalation”.

Another possible reason for a delay in the move towards a military strike was that the US naval battlegroup only left Norfolk, Virginia, 24 hours ago on a 5,000-mile journey to the Middle East.

The 10 warships and two submarines will present the largest American air and naval force since the Iraq war with some 700 Tomahawks ready to be deployed against Syrian targets. Last year, when the US launched a strike following a chemical attack, 59 Tomahawks were used.

After a two-and-aquarter hour emergency Cabinet meeting in Downing Street, No 10 issued a statement that made clear Theresa May and her colleagues agreed action should be taken although the word “military” was not used.

A spokesman explained how the Prime Minister described the Douma attack as a shocking and barbaric act in which men, women and children were killed in the most appalling and inhumane way.

Cabinet agreed the Assad regime had a track record of the use of chemical weapons and it was “highly likely” it was responsible for Saturday’s attack.

READ MORE: Assad did carry out chemical attack on Syrian civilians, claims Macron

The spokesman said: “Following a discussion in which every member present made a contribution, Cabinet agreed it was vital that the use of chemical weapons did not go unchallenged.

“Cabinet agreed on the need to take action to alleviate humanitarian distress and to deter the further use of chemical weapons by the Assad regime.

“Cabinet agreed the Prime Minister should continue to work with allies in the United States and France to co-ordinate an international response,” he added.

Meanwhile, Boris Johnson said Britain had been vindicated over the Salisbury nerve agent attack, after the international chemical weapons watchdog, Organisation for the Prevention of Chemical Warfare, said it agreed with the UK’s conclusions about the poisoning.