Courtesy Larry Jacquez
A video recorded by Facebook user Larry Jacquez shows the police response following the shooting in Farmington on Monday.
CNN  — 

The 18-year-old gunman who shot and killed three people and wounded six others, including two law enforcement officers, in Farmington, New Mexico, used three guns, the city’s police chief said Monday in a video news statement.

Police Chief Steve Hebbe said the assailant, who was killed by responding officers, used an AR-15-style rifle and two other guns as he roamed a quarter-mile area through a neighborhood Monday morning.

The gunman killed three people, wounded two law enforcement officers and four civilians. He shot at least six houses and three vehicles before he encountered Farmington Police officers shortly after 11 a.m. MDT.

The rampage seems to be random, the chief said.

“There were no schools, no churches, no individuals targeted,” he said, adding the shooter appeared to fire at what “entered his head.”

San Juan Regional Medical Center in Farmington received seven patients, spokesperson Laura Werbner told CNN in an email. Werbner said she could not comment on the patients’ conditions.

The chief said a New Mexico State Police officer who was shot drove himself to the medical center and is still hospitalized.

“He’s doing well at this moment,” Stebbe added.

A Farmington Police officer who was also wounded by gunfire has already been released from the hospital, the chief said.

“The event is difficult to understand, how something like this happens,” he said. “But we are doing the best that we can to piece through (evidence), and talk with family members of the suspect to piece through what was going on” and determine a motive, he added.

The crime scene is “wide and complex” and it will take time to figure out what happened, Stebbe said.

Authorities didn’t identify any victims or the shooter. The chief said police expect to hold another news conference Tuesday afternoon.

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The Phoenix division of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) earlier tweeted that it was “responding to a report of a mass shooting” in Farmington.

New Mexico Gov. Michelle Lujan Grisham said she is praying for the victims and their families and has directed the state to support the investigative efforts of the city and county.

“Although details continue to emerge about this incident, this serves as yet another reminder of how gun violence destroys lives in our state and our country every single day,” she said in a statement. “This administration will not stop fighting the epidemic of gun violence from every angle possible.”

Farmington Mayor Nate Duckett said he has received calls of support from the White House, lawmakers in Washington, the Navajo Nation and mayors throughout the state.

“We are a resilient community, a community that cares for each other,” Duckett said. “In the face of adversity, we must stand together, comfort one another, and make a determined effort to heal these wounds so we can emerge stronger and not allow this act of violence to define us.”

About 46,400 people live in Farmington, which is in northwestern New Mexico, just south of the Colorado state line. It is about 150 miles northwest of Albuquerque and about 50 miles from the Four Corners area where the borders of New Mexico, Arizona, Colorado and Utah intersect.

CNN’s Dave Alsup, Sara Smart and Jamiel Lynch contributed to this reporting.