Surrey RCMP are warning the public after robbers targeted four people who scheduled meet-ups through buying and selling app LetGo.

The app, similar to other online marketplaces like Craigslist or Kijiji, lets users buy and sell secondhand items. The Surrey victims were all robbed after meeting someone to buy a cellphone.

Police describe the suspects as two dark-skinned male teens.

Officers are reminding people using LetGo to always meet in a public place and not to invite strangers into their homes. Police also suggest meeting when it's light outside, and bringing a friend or family member along to the meeting.

Some police forces in the Lower Mainland, like the Vancouver Police Department and the Abbotsford Police Department, have supervised exchange zones at their police stations where people can swap items for money.