Workers leave a business building owned by SC Asset Corp as anti-government protesters gather outside during a rally in Bangkok February 20, 2014. [Photo/Agencies]

"LET THEM COME"

Policeman and protester killed in Bangkok clashes   Thai police start to reclaim rally sites, 2 injured

Yingluck's "red shirt" supporters plan a rally in Korat, northeast of the capital, on Sunday, when they will decide what to do next.

"We are not saying that we want to come out and fight, but it seems that Suthep is challenging us red shirts to come out and face off," spokesman Thanawut Wichaidit said.

"Let them come," Suthep said in a midday speech to protesters at a rally site near Bangkok's central oasis of Lumpini Park. "Do they dare?"

The protests are the biggest since deadly political unrest in 2010, when the red shirts paralysed Bangkok in an attempt to remove a government led by the Democrat Party, now the opposition.

More than 90 people were killed and 2,000 wounded when Suthep, at the time a deputy prime minister, sent in troops.

The protests are the latest instalment of an eight-year political battle broadly pitting the Bangkok middle class and royalist establishment against the mostly rural supporters of Yingluck and Thaksin.

Demonstrators accuse billionaire Thaksin of nepotism and corruption and say that, prior to being toppled by the army in a 2006 coup, he used taxpayers' money for populist subsidies and easy loans that bought him the loyalty of millions in the country's populous north and northeast.

Yingluck has continued her brother's policies, but the rice scheme, which paid farmers way above the market rate, has proved ruinously expensive and has run into funding problems.

Thai rice prices fell 15 percent this week as the government rushed to sell some of its record stockpiles to prop up the scheme.

Thailand's anti-corruption body began an investigation last month into the rice scheme and said on Tuesday it was filing charges against Yingluck. She was summoned to hear the charges on February 27.

Yingluck, who is accused of negligence and dereliction of duty, said in a post on her official Facebook page that the commission should not rush an investigation.

"In my position as prime minister and head of the National Rice Policy Committee I am responsible for policy implementation but, as with all policies, the execution is the responsibility of government officials," she said.

Police have made no further moves against the protesters, whose barricades and encampments are still blocking several big intersections in central Bangkok, since gun battles erupted during a security operation on Tuesday.

Their room for action appears to have been further constrained by a civil court ruling on Wednesday.

The court dismissed a case brought by protest leaders who wanted a 60-day state of emergency announced last month to be declared illegal, but added the government was "not allowed to use clauses in the state of emergency to disperse the protests".