MELBOURNE, Australia — Australian police suspect explosives stashed on Sydney’s outskirts were evidence of a deadly escalation in a campaign of antisemitic arson and graffiti crimes that has been waged in major cities for months, officials said on Wednesday.

Police found a list of Jewish targets together with a cache of Powergel, an explosive used in the mining industry, in a trailer in the outer suburb of Dural on Jan. 19, New South Wales state Deputy Police Commissioner David Hudson said.