LONDON (AP) - Children should be discouraged from using cellular telephones for nonessential calls, a government advisory panel said Thursday, recommending that cell phones carry labels disclosing the amount of radiation they generate.

Although the panel concluded there is no evidence cell phones cause harm, it said it could not rule out the possibility that future research could discover long-term use may be harmful.

``We want to give the public the evidence and let the public make up their own minds about how to go forward with the use of cellular phones,'' said the panel's chairman, Sir William Stewart, a former chief scientific adviser to the government.

In response to public concern over potential harm to children, the scientists advised parents to tell their children to use cell phones only for essential calls and said the industry should refrain from targeting children in marketing campaigns.

It said the old and the sick may also be particularly vulnerable because their resistance is lower.

``We can't really say there's any risk for children, the young, the elderly, the sick or the infirm,'' said panel member Colin Blakemore, a brain development expert from Oxford University.

But if it later emerges that cellular phones cause harm, children may be more vulnerable because their nervous systems are still developing, they have thinner skulls and smaller heads, and they would have a longer liftetime exposure to the radiation, he said.

International guidelines governing the amount of radiation cellular phones can emit already include a substantial extra margin of safety to account for the special concerns of children, the elderly and other vulnerable populations, said panel member Dr. Michael Repacholi, who heads the World Health Organization's program on electromagnetic fields.

The panel said a few preliminary studies have suggested radiation may cause subtle biological changes in the brain, but that does not mean health necessarily would be affected.

The radio waves transmitted by cellular phones mostly come from the antenna. Heat in the handset is not related to radiation, but to the battery depleting with use.

Safety is judged partly by something called ``specific energy absorption rate,'' or SAR. It refers to the rate at which the microwaves are absorbed by tissue in the head of the person using the phone and is measured in watts per kilogram of tissue.

Most countries use the international guidelines governing the SAR values, which are set at 2 watts per 2.2 pounds of tissue. That has a built-in extra margin for those more susceptible to radiation, the World Health Organization says. The United States uses 1.6 watts per 2.2 pounds.

Not all cellular phones have the same rate, and the value partly depends on the design of the handset.

The scientists recommended that the radiowave absorption rate be quoted on the packaging, on the phone itself, in the handset's on-screen menu and on the Internet so consumers can compare rates.

Leaflets explaining the significance of the numbers, as well as the health evidence so far, should be sent to every household in the nation, they said.

The panel also recommended stricter controls on the location of cellular phone masts.

The government said it would act immediately on several of the recommendations, and consider others.

``The government will expect SAR measurements to be displayed at all points of sale and with each cellular phone and on the World Wide Web,'' the Department of Health said in a statement.

The department also announced plans to beef up its research program.

The cellular phone industry praised the report and said it would contribute to a fund for more research and make information on radiation absorption rates readily available to consumers.

Copyright 2000 The Associated Press. All rights reserved.