The Los Angeles International Airport (LAX) returned to normal operation at noon Saturday after about four-hour shutdown due to two separate security incidents, US officials said.

Terminals 6, 7 and 8, which are connected, reopened around 11:00 AM local time (19:00 GMT) and all ticketed passengers were ordered to be re-screened. Long lines of passengers extended from the terminals to the parking lots.

The evacuation of the terminals were ordered after a passenger reportedly walked up the exit lane at the screening station of Terminal 8 and bypassed the security check. The incident happened at 7:30 AM (15:30 GMT).

But the Tom Bradley international terminal reopened about one hour later as federal investigators tried to determine if a small explosion involving flashlight batteries was terrorism or crime-related.

Los Angeles Police Department spokesman John Miller told reporters that authorities concluded that the flashlight explosion appears to be accidental.

"We're fairly comfortable that it was not a terrorist incident," said Miller, adding that all appropriate tests have been made on the flashlight to come to that conclusion.

The explosion occurred at 8:00 AM (16:00GMT) at the screening station of Tom Bradley international terminal, slightly injuring several people. The passenger, whose identifies were not released, was detained for questioning.

During the shutdown, flights were not being allowed to depart, while inbound flights were being allowed to land but passengers were not being taken off the plane. Traffic was diverted from the airport, and vehicles were ordered to park in the parking lots near the airport.

LAX officials described the two events as "two apparently unrelated incidents."

There had been some disruptions of flight schedules, as some departing flights and flights destined for LAX from other cities were delayed during the incidents.

The shutdown of the Los Angeles airport during the busy Labor Day weekend followed a bomb scare Friday at Ontario International Airport in east of Los Angeles that prompted the evacuation of 1,000 people for two hours.

But the suspicious bag that caused the scare later turned out to contain only cosmetics, officials said.

Authorities are especially wary of terrorism at Los Angeles International Airport, among the world's busiest. It has twice been targeted for attacks -- a foiled bomb plot planned for around New Year's Day 2000, and a shooting at a check-in counter that left three dead on July 4, 2002.

(Xinhua News Agency September 5, 2004)