Asian airlines have advised passengers to the U.S. and Britain to be prepared for long delays caused by new security measures implemented in response to what British authorities said was a terrorist plot to blow up commercial jets.

A British Airways plane comes in to land at Heathrow Airport, London

International airports throughout Asia reported few significant delays Thursday, despite crippling backups at London's Heathrow airport, one of the world's busiest.

But many Asian carriers were scrambling to meet new security measures for air travelers announced by the British and U.S. governments, after Britain said it had foiled a plot to blow up planes in mid-flight between the two countries.

Asian airlines began banning all liquids, such as beverages, hair gel and shampoo, in airplane cabins on U.S.-bound flights, in line with new U.S. security measures.

Singapore Airlines spokesman Richard Forshaw encourages passengers to be patient, and comply with the new restrictions. 

"They should expect also stringent security screenings at airports, will mean they should get to the airport early, check in as early as possible, and be prepared to undergo several rounds of security screening," said Mr. Forshaw.

Asian airlines' Web sites Thursday also alerted passengers that British transport officials have initiated new security guidelines for all flights departing British airports.

British Airport Authority spokesman Tony Douglas says the restrictions cover carry-on luggage, and most personal items are banned.

"These measures will prevent passengers from carrying hand-luggage into the cabin of the aircraft," said Mr. Douglas.

Small items, such as wallets, baby food and prescription medicines are permitted, with some limitations. All other carry-on items, such as handheld electronics or handbags must be stowed in the plane's cargo hold.

Passengers on flights to Britain are not currently required to meet these new security guidelines. But airlines in Asia on Thursday were encouraging passengers traveling through British airports to voluntarily comply with the restrictions to speed security screening.