Six Philadelphia police officers have been shot during a three hour standoff with a gunman in the US.
Two officers are reportedly barricaded inside the house in Philadelphia, with six more suffering injuries during the ongoing incident.
The standoff started as officers tried to execute a drug raid on a property in the north of the city.
Television images show hundreds of police surrounding the house, many with guns drawn, as a SWAT team stand by.
"Officers are attempting to communicate with the shooter; imploring him to surrender and avoid further injuries," tweeted Philadelphia Police spokesman Eric Gripp.
Police told local residents to remain inside their homes and stay out of the area after hundreds of rounds were exchanged.
Local television station Fox 29 reported some kind of movement by police around 7.30pm local time with a "bang" sound.
Two other officers were also injured in a car accident while responding to the shooting.
There were reports the shooter was livestreaming the incident on Facebook.
President Donald Trump has been briefed on the shooting and was monitoring the situation.
"Suspect is still firing. STAY OUT OF THE AREA," Gripp tweeted.
Fox 29 reported that two drug squad officers were holding individuals they had arrested while serving a warrant, with both officers barricaded inside the house with the suspects.
The shooter was firing into the ceiling of the structure and outside, Fox 29 reported, citing a senior police official.