"Ruthless" criminals are using fake online adverts for car sales to lure victims into a series of "terrifying" armed robberies, police have warned.
Potential buyers were threatened with machetes, a gun or a hammer before the offenders fled with their cash.
Greater Manchester Police has linked reports of 10 armed robberies across Manchester and Oldham from 19 November up to Wednesday.
The majority of victims were targeted on eBay, the force said.
The reports being linked include:
- A woman who had a gun held to her head when she went to buy an advertised car before being robbed
- A man who had a vehicle-jack thrown through the window of his car and was punched in the face, but managed to escape
- A victim who was threatened by machete-wielding men in balaclavas before they stole a "large quantity of cash"
Detectives are also investigating a further six incidents which have been reported as "suspicious".
No arrests have been made as the investigation continues.
Det Sgt Kat McKeown said: "These offenders are targeting innocent members of the public via the internet and have no compassion at all for their victims who they have subjected to a number of terrifying ordeals.
"They are devious and ruthless and need to be caught and I remind people to say alert and vigilant and report anything suspicious to police immediately."
An eBay spokesman said: "We have suspended a number of accounts and continue to cooperate with the authorities while the investigation is ongoing."