Arson detectives have launched an investigation into a fire that ripped through one of Melbourne’s main synagogues early on Friday in what authorities and the prime minister condemned as an antisemitic attack that threatens the country’s social cohesion.

The details remain sketchy, but police said witnesses had described two suspects in dark clothes and masks who broke windows at the Adass Israel synagogue in the inner-southern suburb of Ripponlea before dawn, poured in liquid and ignited it.