Prime Minister Theresa May has indicated that more evidence is needed before blaming Bashar al-Assad for the latest chemical attack in Syria and taking military action against his regime.

Following phone calls with U.S. President Donald Trump and French premier Emmanuel Macron, No 10 said the international community “needed to respond” but did not confirm Assad was responsible at this stage.

“[The leaders] agreed that reports of a chemical weapons attack in Syria were utterly reprehensible and if confirmed, represented further evidence of the Assad regime’s appalling cruelty against its own people and total disregard for its legal obligations not to use these weapons,” the statement read.

The UK will “continue working closely together and with international partners to ensure that those responsible were held to account”, the statement adds.

Inspectors from the Organisation for the Prohibition of Chemical Weapons (OPCW) are due to visit the Damascus suburb of Douma, where between 40 and 70 people were reported to have been killed in a chlorine attack over the weekend.

The White House was less timid in naming Assad in relation to the strikes, saying in a statement after the call with Mrs. May:

“Both leaders condemned Syrian President Assad’s vicious disregard for human life. The President and Prime Minister agreed not to allow the use of chemical weapons to continue.”

On Monday, President Trump was promising to make a decision on an American response within “24 to 48 hours”, although he now appears to have backed off from that claim.

“If its Russia, if its Syria, if it’s Iran – if it’s all of them together – we’ll figure it out and we’ll know the answers quite soon,” he added, speaking to the press before a Cabinet meeting on the 9th.

.@POTUS Trump condemns the heinous attack on innocent Syrians with banned chemical weapons. #Syria pic.twitter.com/qiEahlL3Ah — Department of State (@StateDept) April 9, 2018

Meanwhile, Russia vetoed a UN Security Council resolution ordering a full investigation into the attack overnight.

Russia’s UN ambassador Vassily Nebenzia accused the U.S. of wanting the resolution to fail “to justify the use of force against Syria”.

The UK’s Ambassador to the UN, Karen Pierce, appeared to diverge from the Prime Minister’s position, claiming: “We as the United Kingdom believe the Syrian regime is responsible for these latest attacks.”

The Foreign Secretary Boris Johnson attacked Russia’s actions at the UN and also appeared to blame Assad’s regime. He tweeted: “Hugely disappointing that Russia vetoed the proposal at the UN for an independent investigation into Syrian chemical attacks.

“Russia is holding the Syrian people to political ransom by supporting a regime responsible for at least four heinous chemical attacks against its people.”