Thailand has mounted one of its biggest security operations in recent history with more than 36,000 military and police to prevent anti-government demonstrators from overrunning a summit of Asian leaders, an official spokesman said Thursday.

The government is still smarting from the storming of the East Asian Summit in April in the seaside city of Pattaya where protesters charged through thin police ranks and forced the evacuation of several leaders by helicopter and boat.

A main protest organizer said no new demonstrations are planned this week.

Leaders of 16 Asian and Pacific nations, including Thai Prime Minister Abhisit Vejjajiva, will gather Friday for an annual conference of the Association of Southeast Asian Nations in Cha-am, a beach resort 120 miles south of Bangkok.

About half of the security forces mobilized have thrown a security cordon around this summit venue, and the others will be on alert in the Thai capital, said government spokesman Panitan Wattanayagorn. He said 20 newly bought bulletproof SUV's will chauffeur leaders to their meetings.

"Security forces have also set up emergency escape routes by land, air and sea," he said. "We don't expect it to be necessary but we want to be ready and to assure leaders that they will be able to meet without distraction."

Security forces have also been empowered to impose curfews and restrict freedom of movement around Cha-am and Bangkok.

Roadblocks were thrown up around the summit venue Thursday. Sniffer dogs patrolled hotels and even local fishermen were stopped from going out to sea.

Thailand has been rocked by years of protests and counterprotests by supporters and opponents of former Prime Minister Thaksin Shinawatra, who was ousted in a 2006 military coup on accusations of corruption, abuse of power and disrespect to the country's monarch.

Nearly 10,000 demonstrators took to Bangkok's streets last Saturday, demanding a pardon for Thaksin and that he be allowed to return from exile.

However, Nattawut Sai-kua, one of the protest leaders, said no demonstrations will be staged during the conference.

"There is no plan to protest or disrupt the summit," he said. He added that a protest letter will be handed to ASEAN representatives outside the security zone.

The three-day conference includes the annual gathering of the 10-member ASEAN leaders and those of China, Japan, South Korea, India, Australia and New Zealand.

ASEAN groups Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam.

ASEAN is due to unveil a human rights body for Southeast Asia, sign a declaration on climate change and discuss food security, disaster management, bio-energy and economic integration. The group aims to set up an economic community by 2015.

China wants to expand regional trade and investment and plans a $10 billion infrastructure building fund to deepen ties with its Southeast Asian neighbors. A free trade zone between China and ASEAN is slated to be completed by January 2010.

As at previous ASEAN conferences, violation of human rights in military-ruled Myanmar, which joined the group in 1997, could cast a shadow over the proceedings. The international community is urging ASEAN to pressure the junta to reform.

The group prefers to steer clear of the internal affairs of its members, and with Myanmar recently allowing detained democracy leader Aung San Suu Kyi contact with Western diplomats and the United States unveiling a new policy of trying to engage rather than shun the country's leaders, the tone at the conference may be more positive.

The leaders of Cambodia, Indonesia and Malaysia were not expected to arrive in time for Friday morning's opening ceremony, Thai Foreign Minister Kasit Piromya said.

Cambodian Prime Minister Hun Sen is hosting an official visit by South Korean President Lee Myung-bak, Indonesia is swearing in a new government and Malaysia's government was presenting its budget to Parliament, he said.