The National Anti-Corruption Commission said that if found guilty of the charges – which relate to a controversial rice subsidy scheme – Prime Minister Yingluck Shinawatra could be removed from office.
The announcement came hours after gunfire and explosions shook an area of the city’s historic district just a short walk away from major tourist attractions, as riot police moved to clear sites of protest rallies.
A policeman was shot dead and three civilians were killed, according to the Erawan Medical Centre. Nearly 60 other people were injured, including one foreigner.
The protesters have staged more than three months of mass street rallies demanding Yingluck’s resignation.
Police launched another operation to reclaim besieged government buildings and clear rally sites on Tuesday, tearing through razor wire and sandbag barricades near the capital’s Democracy Monument.
They met fierce resistance from protesters and were eventually forced to retreat amid gunfire. It was unclear who was shooting.
About 150 opposition demonstrators were arrested at a different rally site at an energy ministry complex in the capital on charges of violating a state of emergency – the first mass detentions during the current protests began.
Thailand has been periodically rocked by mass demonstrations staged by rival protest groups since a military coup in 2006 that ousted then-premier Thaksin Shinawatra, Yingluck’s brother.
Yingluck’s opponents say she is a puppet for her brother Thaksin, a billionaire tycoon-turned-politician who fled overseas in 2008 to avoid jail for a corruption conviction.
The protesters are demanding Yingluck hand power to a temporary, unelected government that would carry out reforms to tackle corruption and alleged misuse of public funds before new elections are held.
The National Anti-Corruption Commission said Yingluck had ignored warnings that the flagship rice policy was fostering corruption and causing financial losses. It summoned her to hear the charges on February 27.
Demonstrators have blocked major intersections in a self-styled shutdown of the capital, although attendance has dropped sharply compared with December and January.
Yingluck’s government held a general election on February 2 to try to ease tensions, but the opposition boycotted the vote, saying it would not end the long-running political crisis.