A summit of Asian leaders in Thailand has been cancelled after anti-government protesters broke into the venue in the resort of Pattaya.
PM Abhisit Vejjajiva declared an "extreme state of emergency" in Pattaya for several hours while the leaders were airlifted from the area.
The Association of South-East Asian Nations (Asean) summit was due to have been held on Saturday and Sunday.
Thailand has been in turmoil, with the opposition demanding fresh elections.
The BBC's Jonathan Head in Bangkok says Thais have spent months organising the summit, but security around the venue collapsed in a matter of hours as thousands pushed their way through the police cordon.
It is a humiliation for the government, our correspondent says. He adds that it raises questions over whether the deep divisions that have emerged in Thai society are also damaging morale in the police and the army.
'Lorries and taxis'
The Asean meeting, called to discuss the global financial crisis, was due to start on Saturday, concluding on Sunday with a summit due to include India, Australia and New Zealand.
But as the talks were due to get under way in Pattaya, thousands of red-shirted supporters of ousted Prime Minister Thaksin Shinawatra smashed into the media centre adjacent to the conference hall.
I have met with other Asean leaders and have told them my decision and they all understood the situation
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