A gunman opened fire at a synagogue in California on Saturday, killing one woman and wounding three other people, police said.

A 19-year-old man named as John Earnest was arrested after the attack, in Poway, north of the city of San Diego.

The synagogue had been hosting a Passover celebration when the gunman burst in, reports said.

Police did not suggest a motive but US President Donald Trump said the attack appeared to be “a hate crime”.

The attack comes exactly six months after a shooting in Pittsburgh in October 2018 in which 11 people were killed, thought to be the worst anti-Semitic attack in recent US history.