Strengthened security checks and new restrictions led to long delays at California's airports on Thursday.

The foiled terrorist plot to blow up flights from Britain to the United States prompted U.S. authorities to raise the alert level to red at all national airports.

"I have taken immediate steps to enhance the security of California's airports and protect the people of this state," California Governor Arnold Schwarzenegger said in a statement e-mailed to Xinhua.

At the Los Angeles International Airport (LAX), passengers are requested to throw away or place in checked luggage liquids, gels, perfume vials and even water bottles and toothpaste tubes. Trash bins at security lines were once full of throw-aways.

Airport officials said large airports, including LAX, suffered long delays in the morning, and even smaller ones saw scenes of unaccustomed delays.

Governor Schwarzenegger has ordered the re-deployment of bomb-sniffing dogs, the California National Guard, and the California Highway Patrol to high priority locations to respond to terrorist threats.

About 300 National Guard troops were expected to be in place by late Thursday at LAX, San Francisco and Oakland airports, the state's three largest airports.

British police on Wednesday arrested 21 British nationals who were in the final stages of a plan to detonate liquid explosives in multiple U.S.-bound airliners. British authorities described the plot as part of the largest and most complex planned attack since Sept. 11, 2001, in which over 3,000 people were killed in the United States.

(Xinhua News Agency August 11, 2006)