After an almost six-hour siege by some 40 police officers and special forces, authorities told the local NBC channel in Denver that they found four bodies in the home they had cordoned off, one of them being that of the suspected assailant.

Another person managed to escape the house as the incident began and alerted police, according to the same TV channel.

The security forces, who were shot at from inside the house, responded by throwing tear gas bombs at the building where the suspect was thought to be holding the other three people hostage.

The siege began at 3:00 a.m. and ended around 8:30 a.m.

Witnesses described how they started hearing shots being fired in the last moments.

The identities and ages of the victims are still unknown, as are the motives for the shooting.

The spokeswoman for the Aurora police, Sgt. Cassidee Carlson, said the fatalities were believed to be relatives of the gunman who started the standoff.

Several homes near the building where the shooter had dug in were evacuated and residents were taken to a fire station.

Aurora is the same town near Denver where last July a young man killed 12 people and wounded another 58 at a movie theater.

The incident comes just three weeks after Adam Lanza, 20, committed suicide after killing his mother and then gunning down 20 children and six adults at an elementary school in Newtown, Connecticut, in a tragedy that has sparked a debate in the United States about gun control. EFE