METHUEN, Mass. — Seven people were shot and wounded, and an eighth was hurt while running away when gunfire erupted at a large gathering of young people in Methuen, Massachusetts, authorities said Sunday.

The gunfire began just before 2 a.m. after hundreds of people gathered for a pop-up party organized on social media, officials said at a news conference. The victims range in age from 17 to 22 years old, officials said. Two of them were in critical condition.

“This is another tragic case of gun violence that brings us together this morning,” said Essex County District Attorney Paul Tucker. “It’s pretty amazing that with the amount of ballistics evidence that we’re recovering that more people weren’t hurt.”

Authorities declined to comment on the number of suspects. No arrests have been made, and no weapons have been recovered.

Metheun Police Chief Scott McNamara said authorities have been monitoring other “hot spots” where such gatherings typically take place, but Sunday’s attack happened in a new location and was the first to turn violent.

“Usually these meet-ups consist of very loud music, disorderly conduct, sometimes drinking,” he said. “We try to take action where we can to discourage it, and we’ve been fairly successful in that regard. Unfortunately we did experience a tragic incident here in Metheun last night.”