Eleven Prince George's County police officers were suspended after an accidental shooting at a holiday party with colleagues left two off-duty officers wounded, police say.

The 11 off-duty officers were attending a party at a house in Brandywine Saturday evening when a handgun was fired once. One officer was shot in the hand. Another officer was hurt by ricochet of the same bullet to the hip.

How the gun went off is under investigation. In the meantime, all 11 officers were suspended from the force.

"There were 11 Prince George's County police officers off-duty inside that house at the time. That's why 11 off-duty Prince George's County police officers have been suspended at this time, while we get to the bottom of how that gun discharged," police spokeswoman Jennifer Donelan said at a news conference Monday.

The officers were treated at a hospital and released Sunday morning, investigators said. They were expected to be OK.

An officer threw the party for members of the county's SWAT team, according to sources close to the investigation. The gun fired was a personal handgun, not a department-issued weapon, police said.

Police said they could not confirm whether officers were drinking alcohol when the gun went off.

The president of the county's police union called the investigation serious.

"They are entrusted to have firearms on them and to use them, and to be in control of those firearms at all times," John Teletchea of the Fraternal Order of Police, Lodge 89, said.