A suspected grenade attack in the heart of Bangkok’s main shopping district killed two people and injured 22 on Sunday, a day after a young girl died and dozens were hurt in an attack on a protest rally.

The Sunday afternoon explosion occurred during an anti-government rally in an area popular with tourists for its street stalls, hotels and proximity to one of the biggest shopping malls in Thailand’s capital.

“A 40-year-old woman and a 12-year-old boy died and 22 people were injured,” the Erawan emergency centre said in an update on its website. Two children are among the injured.

A damaged tuk-tuk was left abandoned on the blood-splattered road as soldiers and police sealed off the area, an AFP photographer saw.

Police said shrapnel fragments indicated the blast was caused by a grenade fired from a M79 launcher.

“We are questioning several witnesses but have still made no arrests,” Police Major General Suebsak Pansura told AFP.

Thailand has seen months of anti-government rallies aimed at ousting Prime Minister Yingluck Shinawatra’s embattled administration.

The protests have been marred by sporadic gun and grenade attacks — mainly in Bangkok — by unknown attackers.

On Saturday a five-year-old girl died and 30 were injured — including another girl — when gunmen sprayed bullets at a anti-government rally in the Khao Saming district of Trat province, 300 kilometres east of the capital.

Thailand has been bitterly split since a military coup ousted Yingluck’s brother Thaksin Shinawatra as prime minister in 2006.

The current unrest is the worst since Thaksin-allied Red Shirt protests against a Democrat-led government in 2010 sparked clashes and a bloody military crackdown that left more than 90 people dead.

In recent months 19 people have died and hundreds more have been injured, fuelling fears of a spiral of unrest.

Red Shirt leaders met Sunday in Nakhon Ratchasima, the gateway to the Shinawatra-supporting northeast, to discuss ways to bolster Yingluck’s crisis-hit administration.

Prominent leader Nattawut Saikuar warned the group was now in a “real fight” but refused to elaborate on its plans.

“We will carry on fighting to the end,” he said, amid fears any street action by the group could lead to clashes.

Thailand has been riven by deep political and social divisions since Thaksin’s ousting. Some analysts say the seemingly intractable crisis could lead to protracted violence or a form of wider civil conflict.

The political divide broadly pits the Thaksin-allied rural north and northeast against anti-government protesters — who represent the Bangkok-centred establishment as well as many southerners.

The anti-government movement seized on Saturday’s drive-by attack in Trat as an example of authorities failing to protect rally-goers.

“Weapons of war were used in an act of planned and organised terror,” protest spokesman Akanat Promphan told AFP.

Protesters accuse Yingluck’s billionaire family of using taxpayers’ money to buy the loyalty of rural voters through populist policies such as the rice scheme.

They are demanding she steps down to make way for a temporary unelected council that would oversee loosely defined reforms to tackle corruption and alleged vote-buying.