Police were searching for up to three suspects Wednesday in connection with a deadly mass shooting in San Bernardino, California, where up to 14 people were killed and as many as 14 more were wounded, authorities said.
"The suspects have fled," said San Bernardino Police Chief Jarrod Burguan. "We don't yet have a motive."
The getaway vehicle was a black SUV of some kind, said chief.
"These people came prepared to do what they did as if they were on a mission," he said. "They were armed with long guns, not with handguns."
Burguan warned that the death toll could climb as they continue to search the building. "This is a tragedy," he said.
"We don't know if this is a terrorist incident," added David Bowdich, the FBI assistant director in Los Angeles.
Neither Burguan nor Bowdich would confirm reports that at least one of the suspects was believed to be wearing tactical gear.
Firefighters set up a triage area near the Inland Regional Center on the South Waterman Avenue, where they were treating the wounded on the street and loading others into waiting ambulances for treatment at nearby Loma Linda Medical Center.
Some were transported in the back of pickup trucks.
A KNBC reporter said he saw at least "three bodies on the ground."
Meanwhile, dozens of SWAT team officers were massing outside the facility while police were evacuating the occupants who filed out with their hands up.
Police were also clearing out nearby buildings and marching the occupants out of harm's way to a nearby golf course.
The FBI and federal ATF agents were also heading to the scene, officials said. So was the bomb squad.
"We're still in the process of clearing it," Lawhead said. "We have not given the all-clear yet."
President Obama was briefed by Homeland Security Advisor Lisa Monaco and asked to be updated as the situation develops, a White House official said.
"Absolutely heartbreaking," California Sen. Dianne Feinstein tweeted.
The first shots were fired at the center around 11 a.m. local time (2 p.m. ET), said Lawhead.
Marybeth Feild, president of the center's board of trustees, said she heard from staffers that the gunfire erupted in a conference center.
"That's where the shooting took place," she told NBC News. "I was going to a meeting today, but I wasn't there myself."
Feild said a group of some kind was holding a meeting in conference area "and that's where we're hearing the shooting went into."
"We often let other groups rent out the space," she added. "I'm not sure who was renting it out today, but I believe it was a healthcare event."
Outside, the normally tranquil suburban streets were jammed with police vehicles and first responders.
"There's plenty of police activity," Jim, a sales person at the nearby Structural Material Company who did not give his full name, told NBC News. "A lady ran into our bathroom and said somebody was shooting there."
Jim said police told him and the staff — about 10 to 12 people — to stay inside the building, which is about 200 to 300 yards from the Regional Center, a state-run center for people with developmental disabilities.
The mayhem in California came just days after a gunman barged into a Planned Parenthood facility in Colorado Springs, Colo., killing three people during a five hour siege.
Democrat Hillary Clinton was the first of the presidential candidates to weigh in on the unfolding tragedy.
"I refuse to accept this as normal," she tweeted. "We must take action to stop gun violence now."
She was followed by Democratic rivals Martin O'Malley and Bernie Sanders, and Republican presidential candidates Donald Trump. Ben Carson, Ted Cruz, Jeb Bush, John Kasich, George Pataki, Lindsey Graham and Mike Huckabee.