White House Press Secretary Sean Spicer has been criticised after declaring that Adolf Hitler didn't use chemical weapons during World War II.

"We had someone as despicable as Hitler who didn't even sink to using chemical weapons," said Mr Spicer while talking about Syria.

But critics pointed out the Nazis used gas to kill Jews and others in the Holocaust.

Mr Spicer later clarified Hitler didn't use chemical weapons "in the same way" as Syrian President Bashar al-Assad.