Thailand's parliament was due to hold a special session on Sunday to debate street protests that have undermined Prime Minister Samak Sundaravej, while his supporters planned a counter-rally in the capital, reported reuters. Thousands of anti-government protesters, who say they will not give up until Samak is toppled, are camped in the grounds of his office. No police were visible around the compound on Sunday. Samak remained defiant in a weekly radio address. "I am not afraid but I am concerned about chaos in the nation," he said. "We cannot let the seizure of Government House continue indefinitely without taking action," he added. He flew to see head of state King Bhumibol Adulyadej on Saturday at the king's palace in the coastal town of Hua Hin. Reporters had expected him to make some sort of statement on his return to Bangkok but he avoided them at a military airfield. The violence reached a peak on Friday when Bangkok police fired teargas and rubber bullets to repel an assault on their headquarters by around 2,000 protesters. Unrest has spread around the country, with demonstrators forcing some airports to close and labour unions halting many rail services. The airport on Phuket -- Thailand's second-busiest after Bangkok -- remained closed on Sunday, leaving thousands of foreign tourists stranded on the resort island.