Thai authorities beefed up security in Bangkok's historic center with 2,000 police to protect the Olympic flame from protesters ahead of the torch relay Saturday. Security officials have set up barricades along parts of the 10.5-kilometer (6.3-mile) route, said Gen. Yuttasak Sasiprapha, president of the National Olympic Committee of Thailand. "We are especially concerned about small alleyways from where protesters might emerge as the torch arrives," Yuttasak said. The route, which will start in Bangkok's Chinatown and end at the Royal Plaza, could still be changed or shortened at the last minute if protesters try to disrupt it, he said. Growing criticism of China's human rights record have turned the Olympics, which begin in August in Beijing, into one of the most contentious in recent history. Protests over China's crackdown on Tibetan demonstrations against Beijing's rule have dogged the torch relay at various stops on its worldwide journey that began at the ancient site of the original Olympics in Greece. On Friday, Thai Prime Minister Samak Sundaravej said his government was certain it could provide adequate security and lashed out at anyone who might try to disrupt the relay. "Whoever tries to destroy the flame is crazy and unreasonable," he told reporters. "Why would anyone protest in Thailand? Why don't they protest in China?" The torch arrived by plane Friday under tight security and was quickly whisked to a luxury hotel. Thailand's crown princess welcomed the flame shortly after its arrival. "This is a good thing for Thailand," Samak said. "Thai people should be proud." A coalition of human rights and other activist groups in Thailand said they would hold a peaceful protest outside the UN's Asian headquarters, which is along the planned relay route in Bangkok. "We want to show the Chinese government that the crackdown in Tibet did not spark outrage only in the Western world," said Pokpong Lawansiri, coordinator of the Free Tibet Movement. The protesters will be holding placards and mock coffins as well as distributing pamphlets, he said. Bangkok Metropolitan Police Chief Asawin Kwanmuang said more than 2,000 uniformed and plainclothes police officers, along with hundreds of other crowd control and security personnel, would be deployed. "We have also asked officials to make sure there are no anti-China signs and banners on buildings in the area," he said. "That would be embarrassing." A police helicopter will follow overhead as the torch passes through the capital's historic sites including the Temple of the Emerald Buddha, the ceremonial Grand Palace and the Chitralada Palace, the royal residence. Police motorcycles will ride beside runners as police vans follow in case the athletes need to jump inside for safety, Asawin said. Authorities warned that any foreign activists who try to disrupt the event would be deported. "Supporters of the Tibetan cause have the right to express their views but not to thwart the relay. We will not tolerate that," Yuttasak said. The torch was scheduled to leave for Malaysia on Saturday night.