Two people were killed and 19 young people wounded in a shooting early Sunday at a block party in Detroit, police said.

Though Michigan State Police said no arrests had been made, local NBC affiliate WDIV reported that a 22-year-old suspect was in custody at a local hospital.

The two deceased victims were a 21-year-old man who was shot in the back and a 20-year-old woman who was shot in the head, according to WDIV. All the victims were between 17 and 28 years old, cops said.

A 17-year-old girl was in critical condition, 13 victims were in serious condition and three people were in stable condition at a local hospital, WDIV reported. The 22-year-old suspect was also in stable condition after being shot in the leg, police said.

It is unclear what sparked the shooting, which occurred near an intersection on Detroit’s east side around 2:30 a.m., according to The Detroit News. Police did not publicly speculate on a motive or describe any reason the suspect might have opened fire on the large gathering.

The Sunday morning shooting was the second mass shooting in the Detroit area over the long holiday weekend. Early Friday morning in the suburb of Pontiac, five teenage boys were wounded in a shooting at a large party.

According to police, a fight erupted on Pontiac street, and someone pulled a gun and fired into the crowd. Three 14-year-old boys and two 15-year-old boys suffered non-life-threatening injuries, cops said. No arrests have been made.

Across the country, at least 33 people were killed in various shootings and violent incidents during the extended Independence Day weekend, according to The Associated Press. The deadliest single incident occurred in Kentucky, where four people were killed and three others wounded in a shooting at a home in Florence, a far southwest Cincinnati suburb.

There have now been 278 mass shootings across the U.S. in 2024, according to the Gun Violence Archive. That includes 17 such shootings in the past four days, since July 4. The Gun Violence Archive defines a mass shooting as any shooting with at least four gunshot victims, not counting the shooter.