ST. PAUL  — Two law enforcement agencies in eastern Minnesota are warning residents after a series of overdoses they say may be linked to a potent batch of heroin mixed with other drugs.

The Washington County Sheriff’s Office and the St. Paul Police Department issued alerts Wednesday, the Star Tribune reported. Both the city and county and located in the Twin Cities metro area.

Washington County officials announced that four people have died of suspected overdoses in the last two weeks. The overdoses could involve heroin or other narcotics mixed with fentanyl, according to authorities.

St. Paul police said five people overdosed on a “bad batch” of suspected heroin in a 36-hour span. Investigators believe the drug was laced with other illicit chemicals that made it more hazardous.

Police spokesman Steve Linders said all five people who overdosed survived.

The department told residents to call 911 immediately if they or someone they know is experiencing an overdose. Police also recommended administering the opioid antidote naloxone on anyone experiencing a suspected overdose.

They told community members to share the information with anyone they know who uses heroin.

Other area communities have also reported a string of overdoses recently. In South St. Paul, police said six people overdosed at a home last Saturday.

“At this time we believe the cause was an accidental overdose from an unknown substance,” said Bill Messerich, the city’s police chief.

It’s unclear if the incident was related to those in Washington County and St. Paul.