LOS ANGELES - Authorities in the US state of Colorado confirmed that at least four police officers and an undetermined number of civilians were injured in an ongoing active shooter situation in a building where a planned parenthood clinic is located in Colorado Springs of the state Friday.

Officers from the Colorado Springs Police and the Colorado State Patrol are at the scene, wielding guns.

The suspect holed up inside the building hosting the Colorado Springs branch of Planned Parenthood facility, the police told local media.

"The situation is still unstable, and the shooter is not contained," Police Lt. Catherine Buckley was quoted by the Denver Post as saying,

More than a dozen police vehicles and ambulances are at the scene. A SWAT truck was seen evacuating people from the clinic.

At 2:15 pm local time (2115 GMT), the police department tweeted that officers were "encountering gunfire" from a suspect inside the Planned Parenthood building.

Colorado Governor John Hickenlooper issued a statement, saying "We hold the Colorado Springs community in our thoughts and prayers. The bravery and courage of local law enforcement officers have prevented a dire situation from being far worse, and we are all grateful."

"All state Public Safety resources are at the ready, if and when needed,"he added.