Three people were killed and two others wounded in a shooting on Thursday morning at a business park area in Harford County, U.S. east state Maryland, the authorities said.
A shooter opened fire at a Rite Aid distribution center in Aberdeen, local media reported.
Local WBAL TV station reported that the suspect is a female and has been taken to a hospital, quoting law enforcement source.
"What I understand is the location is secure," Rite Aid spokeswoman Susan Henderson told CNN.
"The distribution center is where products are received and processed for delivery," she said. "This is part of a large facility that is a distribution center. The shooting happened adjacent to the primary building."
Henderson said about 1,000 employees work at the drugstore's Aid support facility.
A caller, identifying herself as Alexi, told local WBAL TV station her mother had texted her to report a shooter in her building. The mother finally responded to another family member after 90 minutes to report she was safe.
Following the shooting, Maryland Governor Larry Hogan tweeted that his office was closely monitoring the "horrific shooting" in Aberdeen.
One day earlier, at least four people were injured in a shooting at a judge's office in Fayette County, Pennsylvania. The shooter was reportedly dead on the scene.
The Fayette shooting came just hours after a gunman opened fire on Wednesday morning at a Wisconsin software company, wounding four people before being killed in a shootout with police.
