GENEVA, Jan 22: Key members of the World Health Organization (WHO) agreed on Thursday to back a worldwide drive against obesity, but health activists warned that the plan could still be diluted.

The United States, which had expressed some reservations about the WHO's Global Strategy on Diet, Physical Activity and Health, joined other executive board members in voting to send it to the agency's annual assembly in May for final approval.

"We are very much in favour of this resolution (to send it to the assembly)," U.S. Health and Human Services Secretary Tommy Thompson told journalists after the meeting.

But while supporting the need for a global campaign against poor diets and lack of exercise, which the WHO blames for soaring rates of cardiovascular disease and diabetes, the United States wants more work done on some details.

Non-governmental organisations (NGOs) believe Washington is bowing to pressure from its powerful food industry to soften the plan, weaken its call to governments to use weapons such as taxation and advertising restrictions to change eating habits, and leave everything up to individual choice.

At the insistence of Washington and some allies, including small sugar-producing states, the plan will be open to further revision until the end of February.-Reuters