US President Donald Trump has lashed out at Syrian President Bashar al-Assad and his allies Russia and Iran over a suspected chemical attack, saying there will be a "big price to pay". Scores of people are said to have been killed in an attack on the rebel-held town of Douma .The UK called for an urgent inquiry while Pope Francis said nothing could justify using chemical weapons. Both Syria and Russia deny a chemical attack took place. In a series of tweets, Mr Trump described President Assad as an "animal".