MANILA, Philippines (AP) -- The World Health Organization has expressed concern that the Philippines is encouraging smoking by hosting one of the world's largest tobacco trade shows.

The two-day fair called ProTobEx ASIA opened Wednesday in the capital's Pasay city for the second consecutive year. Organizers said they chose the Philippines over other locations in Asia because of its vibrant tobacco industry and the "phenomenal" support of the Pasay city government.

Organizers said that Pasay city authorities waived a ban on indoor smoking at the venue, the World Trade Center, but Pasay Mayor Antonino Calixto said that the application was denied.

"Attendees should refrain from puffing cigarettes inside the venue," he said. "If they do so, they would violate existing laws against smoking."

He said the city would send inspectors to check on compliance.

The media was barred from the conference Wednesday and organizers could not be reached for comment. Anti-smoking protesters held a rally outside the venue calling for the fair to be closed.

Senior WHO adviser Eigil Sorensen said that the Philippine government is a signatory to the international Framework Convention on Tobacco Control, which bans tobacco advertising, promotion and sponsorship.

"The exhibition should not be used to promote tobacco," he said in an interview. "We are against any activity that promotes tobacco use, and our advice to the government is to withdraw any endorsements."

The U.N. agencies in the Philippines, including WHO, wrote to President Benigno Aquino III on March 11 to cite the government's commitment to regulate tobacco in the country and protect Filipinos from its harmful effects.

Last year, former Philippine finance and health secretaries criticized a similar event, but Aquino had sent a welcome note, saying the trade show benefited the economy.

Close to 14 million adult Filipinos smoke every day and an estimated 10 die each hour from tobacco-related diseases, WHO says.

The Philippines has one of Asia's highest smoking rates, and had some of the lowest prices for tobacco products before a "sin tax" law took effect this year. It is gradually increasing tax on cigarettes to 30 pesos ($0.72) or more per pack by 2017, roughly doubling the current price. By comparison, a pack of cigarettes costs about $1 in Laos, $3 in Malaysia, $6 in Hong Kong and $9 in Singapore.

Sorensen said that aggressive cigarette advertisements and promotions, such as the Manila event, have been shown to entice young people to start smoking early and keep them hooked.

"Despite the significant decrease in the prevalence of smoking among youths 13 to 15 years old, the tobacco epidemic in the country remains a serious one," he said.

One in 10 youths smoked in 2011, compared to two out of 10 in 2007, according to the Philippine Department of Health.

The tobacco fair organizers said in their promotional statement that the event will feature the latest innovations in primary processing, cigarette making and packaging.

The Philippines is home to major cigarette and cigar manufacturers such as PMFTC Inc., owned by Philip Morris International Inc., which bought local Fortune Tobacco Corp. in 2010.

Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.