A soldier walks behind a tuktuk, or mini-taxi, at the scene of an explosion littered with blood and small pairs of shoes at a main protest site in Bangkok, Feb. 23, 2014. Wally Santana/AP

A bomb killed two people and wounded at least 22 others in a busy shopping district in Thailand's capital on Sunday, hours after a shooting attack on a crowd of anti-government protesters left a child dead and more than 30 wounded.

The bomb, planted in a tuktuk – a motorized mini-taxi iconic of Bangkok – exploded at one of the few large anti-government protest sites remaining, near Ratchaprasong intersection, leaving blood and sandals on the streets.

“A 40-year-old woman and a 12-year-old boy died and 22 people were injured,” the Erawan emergency center said on its website.

The explosion targeted a crowd near a stage used for rallies held by the anti-government People’s Democratic Reform Committee (PRDC), the Bangkok Post newspaper reported. Police said the main suspect in the attack had been arrested.

Leaders of the pro-government United Front for Democracy against Dictatorship (UDD) – or “Red Shirts” – had earlier vowed to "deal with" anti-government leader Suthep Thaugsuban, setting the scene for further confrontations between pro- and anti-government groups.

The UDD said their four main targets will be the PDRC, led by Suthep; the “fraudulent independent agencies of the aristocratic elite;” the judicial system, and the potential use of the armed forces for a coup, local media reported.

“We will continue to fight … so that our long struggle will not be in vain. We have been fighting for eight years in a democratic movement. Today, we can’t afford to yield to hooliganism,” UDD chair Tida Tawornseth said. “We will fight until victory.”

The Bangkok blast followed a separate attack on another anti-government protest rally east of the capital on Saturday night. Assailants threw explosive devices and fired automatic weapons in the Khao Saming district of Trat province, killing a 5-year-old girl and wounding 41 other people. Khao Saming is 186 miles east of Bangkok.

PDRC spokesman Akanat Promphan said: “This attack was carried out by people who disagree with the PDRC in what was clearly a well-organized strike using M16s and grenades.” There were about 2,000 people in the crowd when the attack took place.

While protesters have repeatedly failed in their attempts to force Prime Minister Yingluck Shinawatra out of power, they have blocked her from working at her normal offices and have sent roving mobs after her, making it difficult for her and cabinet colleagues to make public appearances.

Anti-government demonstrators also have succeeded in delaying completion of an early election called by Yingluck, undermining efforts to restore political stability.

The recent unrest is the latest chapter in a political conflict that has gripped Thailand for eight years and broadly pits Bangkok's middle class and elite, and their followers in the south of the country, against rural backers of Yingluck and her brother, who have strong support in the largely rural northern and northeastern Thailand.

A total of 17 people have been killed and nearly 800 wounded since the latest round of protests hit Thailand in November last year, Health Department Chief Suphan Srithammarak said Sunday. The vast majority of the injuries took place in Bangkok, followed by Trat, Pathum Thani, and Rayong.

Anti-government protesters have blocked main Bangkok intersections for weeks with tents, tires 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 protests are the biggest since deadly political unrest in 2010, when Thaksin's “Red Shirt” supporters paralyzed Bangkok in an attempt to remove a government led by the Democrat Party, now the opposition. More than 90 people were killed and 2,000 wounded when Suthep, at the time a deputy prime minister, sent in troops.

Presenting a further headache for Yingluck, Thailand's anti-corruption body filed charges against her last week over a rice subsidy program that has left hundreds of farmers – who have traditionally been her backers – unpaid. Yingluck is due to hear the charges on Thursday.

Al Jazeera and wire services