British scientists have found sarin in samples taken from the site of an alleged chemical gas attack in Syria.

Britain's UN Ambassador Matthew Rycroft told the UN Security Council samples taken from the rebel-held town of Khan Sheikhoun and analysed by British scientists tested positive for sarin or a sarin-like substance.

"The United Kingdom therefore shares the US assessment that it is highly likely that the regime was responsible for a sarin attack on Khan Sheikhoun on 4 April," Mr Rycroft told the UN Security Council.

Britain backs US strike on Syrian air base after 'barbaric' chemical attack

The majority of the international community has blamed the attack, which killed 87 people including many children, on Syria's President Bashar al-Assad.

Turkey has also claimed to have found evidence of sarin gas use after testing the bodies of the victims.

The Syrian government has denied involvement in the toxic attack and blamed rebel groups.

In pictures: US missile strike against Syria Show all 7 1 /7 In pictures: US missile strike against Syria In pictures: US missile strike against Syria The guided-missile destroyer USS Porter (DDG 78) launches a tomahawk land attack missile in the Mediterranean Sea AP In pictures: US missile strike against Syria The United States military launched at least 50 tomahawk cruise missiles at al-Shayrat military airfield near Homs, Syria, in response to the Syrian military's alleged use of chemical weapons in an airstrike in a rebel held area in Idlib province EPA In pictures: US missile strike against Syria Shayrat airfield in Syria Getty Images In pictures: US missile strike against Syria US Navy guided-missile destroyer USS Ross (DDG 71) fires a tomahawk land attack missile in Mediterranean Sea Reuters In pictures: US missile strike against Syria US Navy guided-missile destroyer USS Ross (DDG 71) fires a tomahawk land attack missile in Mediterranean Sea Reuters In pictures: US missile strike against Syria President Donald Trump speaks at Mar-a-Lago in Palm Beach, Fla., after the US fired a barrage of cruise missiles into Syria in retaliation for this week's gruesome chemical weapons attack against civilians AP In pictures: US missile strike against Syria Syria's President Bashar al-Assad Reuters

Mr Rycroft called on all 15 members of the UN Security Council to to support a resolution drafted by the UK, France and the United States to condemn the reported use of chemical weapons and demand all parties provide speedy access for investigators.

He said Russia, a close ally of President Assad, has a choice of sticking with "the toxic Assad regime that poisons its own people" or seeking peace through negotiations and a political transition.

Russia's Deputy Foreign Minister Gennady Gatilov has said Russia would veto the draft in its current form, the Interfax news agency reported.