Bangkok - Dozens of people were wounded in Thailand's capital on Friday when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year.
The movement's leader, Suthep Thaugsuban, was in the procession but was not wounded in the blast, protest spokesperson Akanat Promphan said.
Akanat said an explosive device was thrown into a truck driven by demonstrators that was several dozen meters ahead of Suthep. He said 20 people were injured, while the city's emergency services centre put the toll at 28.
Thailand has been wracked by repeated bouts of unrest since the military ousted former premier Thaksin Shinawatra in 2006 amid charges of corruption and alleged disrespect for the monarchy. The crisis boiled over again late last year after a failed ruling party bid to push through an amnesty bill that would have allowed Thaksin to return from exile.
Anti-government demonstrators who are seeking to oust Thaksin's sister, Prime Minister Yingluck Shinawatra, have taken over seven key roads and overpasses in Bangkok this week, blocking them off with sandbag walls and steel barricades.
The protests, which are also aimed at derailing 2 February elections, have been peaceful. But small acts of violence have reported nightly at protest venues, which have been targeted in shooting attacks and with small explosives hurled at the homes of top protest supporters.
Overnight, two motorcycle-riding suspects drove past the residence of Bangkok Governor Sukhumbhand Paribatra and hurled a grenade inside, according to Police Colonel Samarn Rodkamnerd. Sukhumbhand, who is member of the Democrat Party which is backing the protesters, was not home at the time and no injuries or serious damage was reported.
The attack was similar to another grenade attack on the home of Abhisit Vejjajiva, a former Democrat premier whose party lost to Yingluck's in a 2011 vote.
The violence comes as pressure mounts against Yingluck to resign. She is facing fresh legal troubles after the country's anti-corruption commission announced late on Thursday that it would investigate her handling of a controversial rice policy.
Under the policy, the government buys rice at above-market prices from rice farmers, mostly in the north and northeast, and sells it to other countries.
Critics say the government has been deliberately opaque in its transactions, saying the policy will bring the country to the brink of financial ruin. Last year, Thailand lost its place as the world's leading rice producer.
Yingluck's opponents, largely from the south and urban middle and upper classes, say she is carrying on the practices of her billionaire brother by using the family fortune and state funds to influence voters and cement her grip on power.
But she has widespread support among Thailand's poor majority in the countryside because of the populist policies carried out by her brother, who lives in self-imposed exile to avoid being imprisoned on a corruption conviction.
Since the latest wave protests started in November, at least eight people have been killed and more than 450 have been injured.