GARY, Ind. -- Seven people were shot, at least one sustaining serious injuries, in a single incident early Sunday at a nightclub in Gary, Indiana, authorities said.

One man involved in the shooting is in custody and officers are seeking another, Gary police Detective Sgt. William Fazekas said.

Police have described the incident as isolated.

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Fazekas said most of the victims were in stable condition and receiving treatment at hospitals. However, he said one victim was taken to a hospital in Chicago, about 25 miles away, with more serious injuries.

Police found four male and three female victims at Dirtty's Jazz and Blues Club. An eighth person hurt his leg while trying to get to safety.

Fazekas told The Chicago Tribune that police have not yet identified a motive.

There were no other details related to suspects, victims or circumstances of the shooting at the venue on the city's east side. Lt. Dawn Westerfield, a spokeswoman for the department, said she expected to have more information later Sunday or early Monday.

A representative of the club did not immediately return a message from The Associated Press seeking comment.