BANGKOK (AP) - Thailand's leader warned violence was on the rise in Bangkok and hinted Sunday that a curfew may be imposed on the sprawling metropolis of more than 10 million people after three days of rolling street battles that have killed 25 people.
A towering column of black smoke rose over the city Sunday as protesters facing off with troops set fire to tires serving as a barricade. Elsewhere, they doused a police traffic post with gasoline and torched it.
Schools were ordered shut Monday due to the violence that has killed 25 people since a military operation began Thursday to seal off a 1-square-mile protest camp occupied for weeks by anti-government demonstrators demanding early elections.
Speaking on his weekly television program, Prime Minister Abhisit Vejjajiva insisted that the military operation to quell protests was the answer in ending the country's two-month-long crisis.
"Overall, I insist the best way to prevent losses is to stop the protest. The protest creates conditions for violence to occur. We do realize at the moment that the role of armed groups is increasing each day," he said.
He said his deputy prime minister and the military were meeting to discuss a possible curfew. Abhisit said he had asked the education minister to postpone the beginning of a new school semester, due to begin Monday, for a week.
The spiraling violence has raised concerns of sustained, widespread chaos in Thailand - a key U.S. ally and Southeast Asia's most popular tourist destination that promotes its easygoing culture as the "Land of Smiles."
On Saturday, soldiers blocked major roads and pinned up notices of a "Live Firing Zone" in one area of Bangkok.
The protesters launched a steady stream of rudimentary missiles at troops who fired back with live ammunition in several areas around a key commercial district of Bangkok.
Army snipers were perched with high-powered rifles atop tall buildings, viewing the action below through telescopic sights. Thick black smoke billowed from tires set ablaze by demonstrators as gunfire rang out.
Protesters dragged away the bodies of three people from sidewalks - shot by army snipers, they claimed.
The protesters have occupied a tire-and-bamboo-spike barricaded, 1-square-mile (3-square-kilometer) zone in one of the capital's ritziest areas, Rajprasong, for about two months to push their demands for Abhisit to resign immediately, dissolve Parliament and call new elections.
The violence ignited after the army started forming a cordon around the protesters' encampment and a sniper shot and gravely wounded a rogue general reputed to be the Red Shirts' military adviser.
At least 54 people have been killed and more than 1,600 wounded since the protests began mid-March, according to the government. The dead include 25 killed since Thursday.
The clashes are the most prolonged and deadliest bout of political violence that Thailand has faced in decades despite having a history of coups - 18 since it became a constitutional monarchy in 1932.
The crisis had appeared to be near a resolution last week when Abhisit offered to hold elections in November, a year early. But the hopes were dashed after Red Shirt leaders made more demands.
The political uncertainty has spooked foreign investors and damaged the vital tourism industry, which accounts for 6 percent of the economy, Southeast Asia's second largest.
The Red Shirts, drawn mostly from the rural and urban poor, say Abhisit's coalition government came to power through manipulation of the courts and the backing of the powerful military, and that it symbolizes a national elite indifferent to the poor.
The fighting is taking place in the no man's land between the encampment and the army cordon, a normally bustling area with hotels, businesses, embassies, shopping malls and apartments. Most of them are now shut and public transport is off the roads.
The army said its cordon has been effective, and the number of protesters at the encampment has dwindled by half. Water and power also were cut off to the area Thursday.
About 5,000 hard-core demonstrators held their ground under threat of military operations to oust them, down from about 10,000 days earlier, army spokesman Col. Sansern Kaewkamnerd said.
"If the protesters will not end the situation, we will have to enter the encampment," Sansern said.
The army says it is not shooting to kill, but protesters crawled along sidewalks to slowly drag away corpses of three people near the city's Victory Monument traffic circle in the Ratchaprarop area. Demonstrators accused army snipers of shooting all three in the head.
On Saturday, soldiers unrolled razor wire across roads leading to Ratchaprarop - a commercial district north of the main protest site - area and pinned up Thai and English-language notices saying "Live Firing Zone" and "Restricted Area. No Entry."
Ratchaprarop houses high-rise buildings, posh hotels and designer shops. It was the scene of some of the worst fighting Friday night between troops and anti-government protesters.
The New York-based Human Rights Watch on Saturday called on the Thai government to revoke the fire zones and negotiate an end to the fighting.
"By setting out these 'live fire zones' the Thai authorities are on a slippery slope toward serious abuses. It's a small step for soldiers to think 'live fire zone' means 'free fire zone,' especially as violence escalates," the human rights watchdog said in a statement.
The Red Shirts especially despise the military, which had forced Thaksin Shinawatra, the populist premier favored by the Red Shirts, from office in a 2006 coup. Two subsequent pro-Thaksin governments were disbanded by court rulings before Abhisit became prime minister.