An explosion has killed two people and wounded more than 20 others near a protest site in a busy shopping district of the Thai capital Bangkok.
One of those who died in the attack near the Central World shopping mall was a boy aged about 12 years old.
It came hours after gunmen opened fire on an anti-government rally in eastern Thailand, killing a five-year-old girl.
Tensions across Thailand have escalated since a wave of anti-government protests began in November.
The demonstrators want Prime Minister Yingluck Shinawatra to resign to make way for an appointed interim government, but she has refused.
Last week, several people were killed in clashes that erupted in Bangkok when police began clearing protest sites.
A protest leader, Sathit Wongnongtoey, said Sunday's blast in central Bangkok was caused by a grenade. Six anti-government protesters were hurt on Friday night by a grenade attack in the same area.
In the earlier attack in eastern Thailand, attackers threw explosives and shot at demonstrators at a rally called by the People's Democratic Reform Committee at a night market in the Khao Saming district of Trat province late on Saturday.
Officials said the five-year-old girl had been standing at a noodle stall when the attackers, in two pick-up trucks, opened fire at the PDRC rally. She died from a gunshot wound to the head.
At least 30 other people are believed to have been injured. Another child is said to be in a critical condition.
