Armed Hawai'i National Guard troops may be sent to airports across the state as early as today to ensure that passengers abide by the new carry-on restrictions regarding liquids and gels.

But as Hawai'i airports joined a security crackdown yesterday after a foiled terrorist plot in London, state and federal officials said they could not say how long passengers would be asked to follow the tighter travel restrictions.

For the foreseeable future, passengers will be prohibited from carrying all liquids, lotions and gels onto planes. And they are being subjected to additional security screening at gates. The extra precautions are creating long lines at airports across the country.

"We have our troops on stand-by, ready to assist at the gates," said Maj. Gen. Robert Lee, Hawai'i's adjutant general and head of Civil Defense. "They will be in uniform. They will assist Transportation Security Administration to be sure we follow all the requirements in the boarding of all aircraft and to ensure our visitors and travelers safely get on the aircraft and get to their destination."

Guard troops had not been asked to help as of last night, and it was not clear how many were needed, said spokesman Maj. Chuck Anthony. But they could be called up quickly when asked and all would be volunteers, he said.

Anthony said they would be armed, but would not say if their weapons would be loaded.

"We don't talk about that," he said. "They may or may not be loaded, depending on the circumstances."

Passenger carry-on bags were suddenly subjected to intense scrutiny because terrorists planned to hide chemicals in ordinary containers, and then combine them to create explosives, Lee said yesterday.

"Real innocent looking bottles of water or shampoo or gel — we don't know what's in them," he said. "But when mixed together, they could be very serious to the airline and the safety of the passengers on board."

The widespread potential for a problem among passengers meant Hawai'i officials had to respond quickly.

Lee first learned of the foiled plot at 7 p.m. Wednesday during a nationwide conference call with Homeland Security officials. By 8 p.m., he had organized a similar conference call for Hawai'i officials to brief them.

The biggest concern was to somehow ensure that passengers were prepared and reduce lines and tension at Hawai'i airports. Yesterday, state and federal officials in Hawai'i said the effort was extremely successful.

"Today you did not see the mass confusion here like you saw at Mainland airports," Lee said.

The visitor industry also received kudos from security officials.

Marsha Wienert, state tourism liaison, said hotels received a detailed advisory by 10 p.m. Wed-nesday that departing tourists needed to allow extra time to clear security. Additional advisories were sent out yesterday morning.

"And thankfully, the hotels and the accommodations were able to get that information to many of our guests," she said yesterday.

About 75 percent of Japanese departures had the information before they left their hotels, she said.

"Those departures went off very smoothly," she said.

Sidney Hayakawa, federal security director at Honolulu International Airport, said he had enough workers yesterday to alert arriving passengers. He said there was no resistance to the security measures.

"I am proud to say that yes, we had longer wait times, but really no delays at all," he said.

Reach Mike Gordon at mgordon@honoluluadvertiser.com.