The Thai government called in thousands of additional police troops to help bring peace to the capital, where demonstrators have snarled streets for days. A court also issued arrest warrants for several protest leaders.
The deployment of an additional 30,000 troops and police came Friday as anti-government protesters besieged a satellite transmission center just outside Bangkok. They are angry because the government cut off an opposition satellite TV broadcaster.
The army is warning it may use rubber bullets, tear gas and water cannons against the protesters at the site - the first such threats in a month of protests. However, protesters made it to the facility early in the afternoon.
Thousands of red-shirted supports of the United Democratic Front against Dictatorship have rallied daily in Bangkok. They want Prime Minister Abhisit Vejjajiva to step down and call new elections.
Video clip of protesters and police clashes:
Jaran Ditthapichai, a UDD leader, says he does not believe the protests at the satellite facility will lead to bloodshed.
"If the red shirt people confront with the soldier in some place," he said. I believe, I believe the army will tolerate, will tolerate and not be so aggressive."
The protesters largely support Prime Minister Thaksin Shinawatra, who was ousted in a coup in 2006. He lives overseas to avoid a prison sentence on corruption charges.
Sean Boonpracong, a UDD spokesman, says the protesters have gained in confidence since the rallies began in mid-March.
"We have our chances, our chances are a lot better than when we started three weeks ago. So I think we have the initiative, I think the troops are nervous, they don't want to follow the orders, I think we can very well determine our objective today," said Boonpracong.
Government officials have repeatedly said they wish to avoid bloodshed, and are taking a step-by-step approach to ending the protests.
Among those steps, on Friday, a Bangkok court issued arrest warrants for 17 UDD leaders.
The latest rallies are the most serious crisis the 16-month-old government has faced. Mr, Abhisit successfully weathered red shirt protests a year ago. But he is facing increasing criticism from some Thais for not doing more to end the protests, which are costing millions of dollars a day in lost business and tourism.