The death toll in the fresh wave of violence in the Thai capital Bangkok has risen to at least 17 as fighting continues.
Thai troops are clashing with anti-government protesters in Bangkok, with plumes of smoke rising from the city centre, where the protesters are barricaded in a camp.
The Thai army has designated an area of the city as a "live firing zone" in a warning to protesters, the BBC reports.
"No entry" signs have been put up near a barricaded camp where the protesters have been based since March.
Authorities have ruled out negotiations with the red-shirt protesters, who are formally known as the United Front for Democracy against Dictatorship.
UN Secretary General Ban Ki-moon has urged both protesters and the authorities to avoid further violence.
The city's medical emergency centre says all those who have died were Thais. Another 141 people, including some foreigners, have been injured.
A red shirt leader said they will keep on fighting and called on the government to take responsibility for violence during the demonstrations.
Soldiers have set up roadblocks to seal off the area around the wider protest site, which extends for several square kilometres, to stop supporters reinforcing the thousands of protesters already in the camp.
Embassies, including those of New Zealand and Britain, were closed as protesters set fire to a police bus and shot fireworks at troops, who responded with tear gas, rubber bullets and live rounds.
Plumes of smoke could be seen over the city early on Saturday.
Finance Minister Korn Chatikavanij said the security operation would continue. He said the protestors had left the government no option but to secure the site to protect the general public.
Many of the protesters support former Prime Minister Thaksin Shinawatra, who was ousted in a 2006 coup.
They want Prime Minister Abhisit Vejjajiva to dissolve parliament and call fresh elections.
The protesters converged on Bangkok on 14 March and occupied the main shopping district on 3 April. On 7 April, Abhisit Vejjajiva ordered a state of emergency.