At least two people were wounded when multiple gunshots were fired at people attending a funeral in the U.S. state of Wisconsin on Thursday, police said.

The incident came after deadly mass shootings at a supermarket in New York, an elementary school in Texas and a hospital in Oklahoma.

Multiple gunshots were fired into a crowd of mourners at an afternoon grave-side funeral at Graceland Cemetery in Racine, Wisconsin, a suburb of Milwaukee, Racine police Sergeant Kristi Wilcox told reporters.

One of the victims, a young female, was treated at a local hospital and released, but the second victim, apparently suffering more serious injuries, was flown by helicopter to a Milwaukee hospital, Wilcox said.

No suspect was in custody, she said, adding police were asking anyone with information or video footage that might assist investigators to come forward. Asked whether multiple shooters may have been involved, Wilcox said she was "not at liberty to say." And she said she could not confirm initial reports that the shooting may have come from a car.

Mayor Cory Mason issued a statement saying he had ordered police to enforce an 11 p.m. curfew through the weekend for anyone under the age of 18.

"Today's heinous shooting at a cemetery while a family was already mourning the loss of a loved one is a new low for these perpetrators of violence in our community. The violence has got to stop," Mason wrote.

Milwaukee television station TMJ4 News, citing family members attending the grave-side service, said five relatives of the man who was being buried at the time were struck by gunfire, though their conditions were not immediately known.

A man who lives across the street from the cemetery, Rey Brantley, told Milwaukee television station TMJ4 News that he was picking his daughter up from school when he heard gunfire, and that his son was playing basketball nearby and came close to being shot.

"Who in their right mind would go and shoot up a funeral in broad daylight," Brantley said in an on-camera interview. "Those people were attending a funeral."

The shooting came a day after a gunman killed four people and himself at a medical center in Tulsa, Oklahoma.

Nineteen school children and two teachers were shot to death on May 24 during a siege at an elementary school in Uvalde, Texas, that ended when police killed the 18-year-old assailant.

And an 18-year-old avowed white supremacist, also armed with a semiautomatic weapon, killed 10 people, most of them Black, at a supermarket in Buffalo, New York, on May 14 in what authorities said was a racially motivated attack.

The suspect arrested in the Buffalo shooting pleaded not guilty on Thursday to 25 counts in an indictment returned by a grand jury.