Washington has stepped up pressure on Russia to stop supporting Syrian president Bashar al-Assad, with a senior US official saying that the problem in Syria was Moscow’s sponsorship of a “murderous regime”.
Tensions with Moscow have escalated since the US fired missiles at a Syrian air base on Friday in response to a suspected gas attack that killed more than 80 people in northern Syria.
US secretary of state Rex Tillerson, who is due to meet Russia’s president, Vladimir Putin, on Wednesday, said Moscow had failed in its commitments to stop Syria using chemical weapons. Russia intervened militarily in 2015 to back Mr Assad, tilting the balance of the six-year war in his favour.