Los Angeles:
Police sought a motive Saturday after a gunman armed with an assault rifle and a stock of ammunition opened fire at the Los Angeles International Airport, killing a federal official.
The attack Friday, which injured seven other people, caused chaos in the busy US transport hub as panicked travelers bolted after Paul Anthony Ciancia blasted through a security checkpoint.
The 23-year-old then walked calmly through a packed terminal seeking further victims before being shot and wounded by police.
As investigators scoured the LAX crime scene early Saturday, airport officials tweeted that flights would depart from other terminals.
An estimated 1,550 scheduled flights with some 167,000 passengers were impacted Friday amid the resulting ground stop, they said.
The slain official was identified as Gerardo Hernandez, 39, the first Transportation Security Administration (TSA) employee killed in the line of duty since the group was set up following the September 11, 2001 terror attacks.
Ciancia, who reportedly had a grudge against the TSA, was still carrying plenty of ammunition when he was arrested, said Los Angeles Mayor Eric Garcetti.
"There were more than 100 more rounds that could have literally killed everybody in that terminal today," he said.
The mayor ordered flags on city buildings to fly at half-mast in honor of Hernandez.
While reports suggested Ciancia -- who was shot several times before being apprehended -- was a disgruntled loner, the Federal Bureau of Investigation said it could not rule out terrorism.
Authorities have not released information on the suspect's condition.
The shooting took place at the country's third-busiest airport.
He "came into Terminal Three, pulled an assault rifle out of a bag and began to open fire," said Patrick Gannon, head of airport police.
"He proceeded up into the screening area ... and continued shooting," he said.
Police chased the gunman, "engaged him in gunfire ... and were able to successfully take him into custody."
'Disappointment in the government' The FBI said Ciancia was a Los Angeles resident originally from the eastern state of New Jersey.
His motive, however, remained unclear.
Police found a note on him voicing "disappointment in the government" but stating that he did not want to harm "innocent people," a law enforcement official told the Los Angeles Times newspaper.
It appeared that Ciancia was hunting for TSA agents. During the shooting spree, which lasted less than 10 minutes, he approached a number of people cowering in the terminal and pointed his gun at them, asking if they "were TSA."
If they answered "no," he moved on, the Times reported, citing witnesses who said he cursed the TSA repeatedly.
Before the shooting, Ciancia texted his younger brother that he might harm himself, The Washington Post reported. This led the shooter's father to contact local New Jersey police, who in turn contacted their counterparts in Los Angeles.
LAPD officers visited Ciancia's home on Friday but could not find him, according to The Post.
At the airport Brian Adamick, 43, said he saw a wounded TSA worker, with a bloodied ankle, board a shuttle bus helping passengers escape.
"It looked like it was straight out of the movies," he said.
This being Los Angeles, a number of celebrities were caught up in the action.
Filming of an episode of the hit TV show "Mad Men" was halted at nearby Terminal Four, a crew member wrote on Twitter.
Actor James Franco posted a "selfie" picture of himself on a plane stopped on the tarmac by the incident.
"Some s**tbag shot up the place," he wrote in the first of a series of tweets, ending some five hours later with a more relieved message: "WE'RE OUT! - everyone was calm."
The shooting came just weeks ahead of the stressful end-of-year travel period that includes Thanksgiving - traditionally the busiest travel time of the year - and Christmas.