The Islamic State has mocked US President Donald Trump, saying that the country is "being run by an idiot."

In its first official reference to the president who took office in January 2017, the militant group's spokesman Abi al-Hassan al-Muhajer said: "You [the US] are bankrupt and the signs of your demise are evident to every eye."

"There is no more evidence than [that] you being run by an idiot who does not know what Syria or Iraq or Islam is," he said in a recording released on Tuesday (4 April) via a messaging network Telegram.

Washington has yet to respond to the the remarks.