Bangkok: Thailand turned up the legal heat on defiant red-shirted protesters loyal to fugitive ex-premier Thaksin Shinawatra, seeking a court order on Monday to move a crippling rally out of Bangkok`s tourist hub.
Tens of thousands of Thaksin supporters have paralysed a swathe of the capital, causing several major shopping malls to shut and traffic to grind to a halt on a key road through the commercial and luxury hotel district.
Tensions in the capital grew with an early hours blast outside a massage parlour owned by the family of the commerce minister, but police said no one was injured.
Elsewhere, an unexploded hand grenade was found outside the government-run National Broadcasting Service of Thailand, while in a provincial town a grenade was fired into a supermarket parking lot.
The attacks are the latest in a series of unexplained explosions since the rolling demonstrations began in mid-March by Thaksin supporters who are mainly from the rural poor north of the country.
The Reds are demanding immediate elections, accusing Prime Minister Abhisit Vejjajiva`s government of being undemocratic because it took office in 2008 through a parliamentary vote after a court stripped Thaksin`s allies of power.
Abhisit`s government has already banned the Reds` gathering in the tourist hub under a strict security law, threatening protesters with a year in jail.
The authorities stepped up their legal fight on Monday, seeking a court order to increase pressure on the protesters to leave the area.
Senior Reds, however, said they would not be cowed by the threat of arrest, adding they would pass the torch to new leaders if detained.
"Regardless of who brings an arrest warrant to me today I will not accept it," said Jatupron Prompan, a key Reds figure. "There is no law in the world banning its national from using roads."
The military has mounted a heavy security response involving 50,000 personnel to try to contain the protests.
The government, however, wants to avoid a repeat of last April`s clashes with Red Shirts that left two people dead, six months after riot police took on the rival Yellow Shirts in bloody scenes outside Parliament.
On Sunday, deputy prime minister Suthep Thaugsuban, who is in charge of security, said the government wanted to end the standoff peacefully.
"We will avoid force which risks clashes. But we may have to send authorities to the site," he said.
Tourists in the upscale shopping area have appeared largely unfazed by the noisy protests, with some enjoying the rally`s carnival-like atmosphere with dancing and live music in the streets.
Police said up to about 58,000 Reds rallied on Sunday in their trademark colour, surrounding a stage where leaders issued diatribes and sang protest songs.
Business chiefs have warned the action could inflict heavy losses on the tourism and other industries.
But the stock exchange said it would operate as usual Monday, urging investors to "consider the credibility of news sources" on the protests.
Thai society is split between the Reds, who accuse Abhisit`s government of being elitist and Army-backed, and the Yellow Shirts, supporters of the country`s establishment who accuse Thaksin of gross corruption.
Thaksin, a billionaire former telecoms tycoon, lives abroad to avoid a jail term for graft at home.
Thailand has been wracked in recent years by a string of protests by the Reds and the Yellows, whose campaign in 2008 against Thaksin led to a crippling nine-day blockade of the country`s airports.