Thieves this week stole jewellery from a gold Volvo in King's Road, Prestwich, after they smashed its windows to get in.
Witnesses say they saw two men grab a rucksack from the car. They then drove off in a Ford Focus, driven by a third man.
A police spokeswoman said: "One of the men is said to be of stocky build, above 6ft tall with a dark-coloured hooded top. The second offender was smaller with brown hair."
To get more news, click here to sign up for our free daily newsletter.