Thousands of supporters of Thai Prime Minister Yingluck Shinawatra meet on Sunday hours after an attack on an anti-government rally killed two people and wounded 41, media said, raising tension in the country's protracted political crisis.
Gunmen shot at a protest stage and threw grenades in the Khao Saming district of the eastern province of Trat on Saturday evening, media said.
Among the seriously wounded was an eight-year-old girl, who suffered a shot to the head, the Bangkok Post said.
Anti-government protesters have blocked main Bangkok intersections for weeks with tents, tyres and sandbags, seeking to unseat Yingluck and halt the influence of her billionaire brother, Thaksin Shinawatra, an ousted former premier regarded by many as the real power behind the government.
The United Front for Democracy against Dictatorship, a protest movement largely made up of "red shirt" Thaksin supporters based in the populous north and northeast, is holding a meeting of its leaders from across the country on Sunday in Nakhon Ratchasima, northeast of the capital.
Chairwoman Tida Tawornseth said Sunday's rally would consolidate plans to restore democracy after the opposition boycotted and disrupted elections this month, leaving the country paralysed under a caretaker government. She ruled out any plans for violence.
"If we wanted to clash, we would have done so a long time ago," she said on Saturday. "We wouldn't have to wait for this long."
Four protesters and a police officer were killed on Tuesday when police attempted to reclaim protest sites near government buildings. Six people were wounded by a grenade on Friday.