A pop bottle was used to make an explosive device, which was then placed in this now-destroyed mailbox. The device exploded late Saturday night. (Sheryl Rennie/CBC)

A total of four Regina homeowners had their mailboxes destroyed by exploding pop bottles over the weekend, and police continue their search for the culprits responsible.

The bottles, filled with what police are calling a "mixture intended to cause an explosive reaction," were placed in mailboxes at homes in the southeast and the northwest part of the city on Saturday night and Sunday morning, police said.

The first is believed to have taken place at about 10:40 p.m. Saturday at a home on Mayfield Road in the University Park area, but the homeowner didn't notice the damage until the next morning.

The second took place on Pleasant Place just before 11:30 p.m., police said. The home's owner reported hearing voices outside, followed by a loud bang and the sound of a car speeding away, according to police.

A damaged plastic pop bottle and some white-coloured residue were found nearby. The force of the blast ripped the mailbox from the side of the house.

On Monday, police said they attended two similar calls, one on Batoche Street and the other on Forsythe Crescent.

No injuries have been reported.

Police are cautioning the public to call police rather than handle any container or package that looks suspicious.

Spokeswoman Elizabeth Popowich said investigators suspect it's likely teen pranksters behind the mailbox attacks.

"In our experience, when we've been able to lay charges, it's usually a younger person and they're experimenting and wanting to cause some damage or grief and they do it in that way," she said.

Anyone with information is asked to phone police or Crime Stoppers at 1-800-222-TIPS (8477).