Officials at Athens International Airport said yesterday that stricter security measures for passengers flying to destinations in the USA, Great Britain and Canada would continue until further notice, following the discovery last week of an alleged terrorist plot in the UK to blow up airliners on transatlantic flights. Passengers flying to destinations in these three countries will not be allowed to take large items of hand luggage on board the aircraft, officials said. They will also be barred from taking any form of liquid, gel or cream onto the aircraft with them. Olympic Airlines advised travelers headed for these countries to arrive at the airport at least two-and-a-half hours before their flight is due to leave, as the added security is making the check-in process longer. Authorities said that all luggage for flights to the USA, Britain and Canada is being scanned before being loaded onto planes. Airport officials said that the measures would change according to the demands of aviation authorities in these three countries.