3 people killed, one critically injured in a shooting at manufacturing facility in Maryland

• Police responded to shots fired at a manufacturing building in Smithsburg, Maryland, Thursday.
• At least 3 people were killed, and an officer was wounded, according to law enforcement officials.

Three people were killed after a shooter opened fire at a manufacturing building in Maryland on Thursday afternoon, police said.

Law enforcement officials with the Washington County Sheriff's Office responded to reports of gunfire around 2:30 p.m. at Columbia Machine in Smithsburg, Maryland, about 75 miles outside of Baltimore.

Three people were deceased at the scene and another was critically injured, police said in a statement. The suspected shooter fled the scene before a state trooper encountered the suspect's vehicle. The trooper and the suspected shooter exchanged gunfire, and both were injured and transported for medical treatment, p0lice said.

Maryland Gov. Larry Hogan said during a press conference that the officer was shot in the shoulder.

The motive of the suspected shooter, who has not been identified by authorities, remains unclear.

Video footage posted to Facebook by an eyewitness near the scene showed police cars rushing past and gunshots could be heard in the background.

Rep. David Trone of Maryland tweeted that his office was "actively monitoring the mass shooting" and is in contact with officials.

"If you're local, please stay way from the area as law enforcement responds," he said in the hours following the shooting.

The Bureau of Alcohol, Tobacco, Firearms and Explosives office in Baltimore and Maryland state police are also assisting the investigation into the incident.

This story is developing. Please check back for updates.