Bangkok - Two young siblings and a woman were killed in an apparent grenade attack against anti-government protesters occupying an upscale shopping area of Thailand's capital on Sunday, the latest violence in a months-long political crisis that is growing bloodier by the day.
The attack near the Ratchaprasong intersection in the heart of Bangkok, home to major shopping malls and luxury hotels, followed another assault on anti-government protesters in eastern Thailand on Saturday night that killed a young girl and wounded dozens of other people.
A 6-year-old girl, Patcharakorn Yos-ubon, died on Monday from brain and liver injuries, according to Erawan emergency services centre, which keeps track of protest casualties in Bangkok. She died one day after her 4-year-old brother, Korawit, and a 59-year-old woman were killed in the attack.
A 9-year-old boy suffering from brain and lung damage from the explosion remained in the intensive care unit of Ramathibodi Hospital, according to a hospital statement released on Monday.
Erawan centre said Sunday's violence left 21 others injured.
The attacks were the latest in a spate of protest-related violence roiling Thailand over the past three months, with at least 18 people killed and hundreds hurt.
The protesters, who are occupying several key intersections in Bangkok, want Prime Minister Yingluck Shinawatra to quit to make way for an appointed interim government to implement anti-corruption reforms, but she has refused.
On Saturday night, a 5-year-old girl was killed and about three dozen people wounded in an attack on an anti-government rally in the eastern province of Trat.
The perpetrators have not been identified in either attack. Both sides in the ongoing political dispute have blamed the other for instigating violence.
A protest leader, Sathit Wongnongtoey, said Sunday's explosion was caused by a grenade. Six protesters were hurt on Friday night by a grenade attack in the same area.
Explosives experts from the police and army cordoned off the immediate area of the blast to search for clues amid vendors' overturned tables and bloodied sandals. Protesters, meanwhile, continued to rally on streets in the area that they have occupied for several weeks, while soldiers patrolled in combat gear.
While the protesters have failed repeatedly to force Yingluck out through self-declared deadlines, they have blocked the prime minister from working at her normal offices and have sent roving mobs after her, making it difficult for her and Cabinet members to make public appearances.
The protesters also have succeeded in delaying completion of early elections called by Yingluck, undermining efforts to restore political stability.
"I strongly condemn the use of violence in recent days that has caused many deaths both in Trat province and, especially, at Ratchaprasong today, which is particularly saddening and disturbing since the lives of children were lost," Yingluck said in a statement Sunday night.
UN Secretary-General Ban Ki-moon called for an immediate end to the violence from any side, and urged the government to bring those responsible to justice.
Saturday night's attack in Trat, about 300km east of Bangkok, occurred as 500 anti-government protesters were rallying near busy food stalls.
A 5-year-old girl died in the attack, said a nurse at Trat Hospital, Nantiya Thientawatchai.
Police Lieutenant Thanabhum Newanit said unidentified assailants in a pickup truck shot into the crowd and two explosive devices went off.
It was not clear whether the protest group's guards fought back. Thanabhum and other officials said about three dozen people were hurt, several critically.
Both supporters and opponents of the protesters, as well as police, have been victims of the political violence, which before Saturday was mostly confined to Bangkok.
Thailand has seen sometimes violent political conflict since 2006, when then-Prime Minister Thaksin Shinawatra, Yingluck's brother, was ousted by a military coup after being accused of corruption and abuse of power.
Thaksin's supporters and opponents have since taken to the streets for extended periods in a power struggle.
In 2010, pro-Thaksin "Red Shirts" occupied part of Bangkok for two months, and were assisted by their own armed militia. More than 90 people were killed in violent confrontations, with the army finally ordered to sweep away the demonstrators.
The Red Shirts have mostly kept a low profile during the current political unrest, but held a meeting Sunday to discuss how to respond to the crisis.