The province's police watchdog says it is investigating after a 34-year-old man in St. Catharines, Ont., was seriously injured during an altercation with officers.

The Special Investigations Unit says the altercation happened with Niagara regional police officers at a residence in the city Wednesday morning.

In a news release Thursday, the SIU says the man was taken into custody and then transported to hospital where he was diagnosed with a serious injury.

It did not specify what kind of injuries the man sustained.

The SIU says two investigators have been assigned to the case.

It is urging anyone with information or video footage of the incident to contact them.

The SIU is an arm's length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.