Anti-government protesters dug into their encampments around Bangkok and rejected talk of negotiations Sunday after a monthlong standoff escalated into clashes that killed 20 people in Thailand's worst political violence in nearly two decades.

Bullet casings, rocks, pools of blood and shattered army vehicles littered the streets near a main tourist area where soldiers had tried to clear the protesters, who are demanding that the prime minister dissolve Parliament, call early elections and leave the country.

Foreign governments issued warnings for citizens visiting Thailand, where tourism is a lifeblood industry.

On Sunday, protesters showed off a pile of weapons they had captured from the troops, including rifles and heavy caliber machine-gun rounds. More than half a dozen military vehicles, armored personnel carriers, Humvees and a truck, were crippled by the protesters, who ripped off the treads of the armored cars and stood on them triumphantly.

The demonstrators had captured several Thai soldiers who were later released.

On Sunday, the protesters broke into a satellite communications complex in a northern Bangkok suburb, forcing the operators to restore the Red Shirts' vital People Channel television station, which the government has twice shut down.

Jatuporn Prompan, a leader of the Red Shirt movement that contends the current government is illegitimate because it does not reflect results of the last elections, said Prime Minister Abhisit Vejjajiva's hands were "bloodied" by the clashes Saturday night.

"Red Shirts will never negotiate with murderers," Jatuporn announced from a makeshift stage. "Although the road is rough and full of obstacles, it's our duty to honor the dead by bringing democracy to this country."

But another protest leader, Veera Musikapong, called on followers to refrain from further violence against government forces and cooperate with authorities who might come to investigate Saturday's clashes.

"Please don't tarnish the victory we are very close to winning now," he said ahead of funeral rites for 14 dead demonstrators.

Government forces Saturday night moved into a protester-occupied area around Bangkok's Democracy Monument, near the backpacker mecca of Khao San Road. The push instead set off street fighting.

Each side blamed the other for the violence. Red Shirt leaders accused the military of opening fire into the crowds, while army spokesman Col. Sansern Kaewkamnerd accused protesters of firing live rounds and throwing grenades.

Government spokesman Panithan Wattanayakorn said the military only fired live ammunition into the air. He said authorities have found grenades, assault rifles and homemade weapons among the protesters.

Four soldiers and 16 civilians were killed, according to the government's Erawan emergency center. At least 834 people were injured, according to the emergency center. The deaths included Japanese cameraman Hiro Muramoto, who worked for the Thomson Reuters news agency. In a statement, Reuters said he was shot in the chest and the circumstances of his death were under review.

Police spokesman Lt. Gen. Pongsapat Pongcharoen said an autopsy committee, which would include two Red Shirt members, was set up to examine corpses of those killed, including Muramoto.

It was the worst violence in Bangkok since four dozen people were killed in a 1992 antimilitary protest. Late Saturday, army troops pulled back and asked protesters to do the same, resulting in an unofficial truce.

South Korea and China both urged their nationals Sunday to avoid visiting Bangkok. Australia warned its citizens of a "strong possibility of further violence" in Thailand, and Foreign Minister Stephen Smith told tourists to stay away from the protests.

Apichart Sankary, an executive with the Federation of Thai Tourism Associations, said that if street protests continue the number of foreign visitors could drop to 14.5 million this year, against an earlier official projection of 15.5.

The U.S. State Department has not updated a travel alert issued last week when a state of emergency was imposed that advised citizens to be careful when visiting the Thai capital.

The demonstrations are part of a long-running battle between the mostly poor and rural supporters of former Prime Minister Thaksin Shinawatra, and the ruling elite they say orchestrated the 2006 military coup that removed him from power amid corruption allegations.

The protesters, called "Red Shirts" for their garb, see the Oxford-educated Abhisit as a symbol of an elite impervious to the plight of Thailand's poor and claim he took office illegitimately in December 2008 after the military pressured Parliament to vote for him. Thaksin's allies had won elections in 2007 but court rulings removed two governments on charges of conflict of interest and vote-buying.

Saturday's violence and the failure to dislodge the protesters are likely to make it harder to end the political deadlock.

Abhisit "failed miserably," said Michael Nelson, a German scholar of Southeast Asian studies working in Bangkok.

Abhisit went on national television shortly before midnight to pay condolences to the families of victims and indirectly assert that he would not bow to the protesters' demands.

"The government and I are still responsible for easing the situation and trying to bring peace and order to the country," Abhisit said.

Authorities' failure to clear the protest sites raised questions about how much control Abhisit has over the police and army. Arrest warrants have been issued for 27 Red Shirt leaders, but none is known to have been taken into custody.

The Red Shirts have a second rally site in the heart of Bangkok's upscale shopping district, where they remained Sunday even after more troops were sent there Saturday. The city's elevated mass transit system known as the Skytrain, which runs past that site, stopped running and closed some of its stations for the second day Sunday.

Merchants say the demonstrations have cost them hundreds of millions of baht (tens of millions of dollars), and luxury hotels near the site have been under virtual siege.

___

Associated Press writers Grant Peck, Kinan Suchaovanich, Denis D. Gray and Thanyarat Doksone contributed to this report.