BANGKOK – Thailand’s leader defended the deadly army crackdown on protesters besieging the capital’s heart, saying Saturday the country’s very future was at stake. Protesters dragged away the bodies of three people from sidewalks — shot by army snipers, they claim — as soldiers blocked major roads and pinned up notices of a “Live Firing Zone.”

“I insist that what we are doing is necessary,” Prime Minister Abhisit Vejjajiva said on national television, making it clear he would not compromise. “The government must move forward. We cannot retreat because we are doing things that will benefit the entire country.”

On Saturday, 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.

The spiraling violence has raised concerns of sustained, widespread chaos in Thailand — a key U.S. ally and a popular tourist destination that promotes its easygoing culture as the “Land of Smiles.”

“The situation right now is getting close to a civil war each minute,” said Jatuporn Prompan, a protest leader. “Please don’t ask us how we are going to end this situation, because we are the ones being killed.”

Since Thursday, the once-bustling commercial and shopping district has become a war zone with Red Shirt protesters firing weapons, throwing homemade explosives and hurling rocks at troops firing live ammunition and rubber bullets.

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 24 people have been killed and more than 194 wounded since Thursday. Previous violence since the protest began in mid-March caused 29 deaths and injured 1,640.

This is the most prolonged and deadly political violence that Thailand has faced in decades.

The protesters have occupied a tire-and-bamboo-spike barricaded 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 crisis had appeared to be near a resolution recently 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.

The U.S. Embassy said it will evacuate family members of its staff who want to leave Bangkok.

Embassy spokeswoman Cynthia Brown said the U.S. State Department also issued a “travel warning advising all citizens to defer travel to Bangkok.”