Sri Lanka slapped an indefinite curfew in a popular tourist region on Monday after rioting Buddhist mobs killed three Muslims in a surge of religious violence that triggered international concern.
Local community leaders accused authorities of doing little to prevent Sunday night's carnage that made hundreds of Muslims homeless after attacks on their homes, shops, factories, mosques and even a nursery.
The most senior Muslim member of President Mahinda Rajapakse's government threatened to resign at the decision to allow militant Buddhists to rally in the flashpoint region.
"Three deaths have occurred and 78 people have been seriously wounded in the mob attacks... Places of Muslim religious worship have also been attacked with total impunity," Justice Minister Rauf Hakeem said as he toured the damage in the neighbouring towns of Alutgama and Beruwala.
"The government allowed the Bodu Bala Sena (BBS) to hold their gathering and therefore they must take responsibility for what has happened," he said, referring to a hardline outfit better known as the Buddhist Force.
Hakeem told reporters that he was now under pressure from his own supporters to quit the government to protest the failure to prevent the attacks, the latest in a series of violent incidents involving the BBS.
The UN human rights chief Navi Pillay expressed concern that the religious riots could spread to other areas of Sri Lanka and demanded that Colombo immediately bring the perpetrators of Sunday's attacks to justice.
"The government must urgently do everything it can to arrest this violence, curb the incitement and hate speech which is driving it, and protect all religious minorities," Pillay said in a statement issued in Geneva.
"I am very concerned this violence could spread to Muslim communities in other parts of the country," she added.
The United States, which has led international condemnation of Sri Lanka's human rights record, had also urged Colombo to end the violence.
The unrest erupted on Sunday night when followers of the BBS staged a protest over a recent road rage incident in the area.
After stones were allegedly thrown at them, the BBS supporters then tore through the two towns, attacking people on the street and setting fire to property and vehicles.
Local residents said police did little to protect them when the Buddhist mobs started their onslaught around sundown in the mainly Muslim towns which are around 60 kilometres (37 miles) south of the capital Colombo.
Police fired teargas and imposed a night-time curfew but the violence went on for several hours, according to residents.
"We pleaded with the police to come and stop the mob attacking our houses but the police did nothing," said Mujahedeen, a resident of Alutgama's Milton Road where around a dozen buildings were set on fire.
Police chief NK Illangakoon said the situation was "improving" although the curfew would remain overnight Monday.
He said eight people had been arrested in connection with the riots, but added that an unspecified number of them had already been freed on bail.
President urges 'restraint'
Both towns are popular beach resorts frequented by international tourists, but there were no reports of any foreigners or hotels being caught up in the violence.
However, hotels told their guests to remain indoors while Western embassies advised their nationals to avoid travelling to the region.
Rajapakse, currently in Bolivia, said in a statement that he would not allow "anyone to take the law into their own hands" and urged "restraint".
The attacks are the latest in a series of religious clashes to hit the island following unrest in January and also last year when Buddhist mobs attacked a mosque in the capital Colombo.
BBS leader, Buddhist monk Galagodaatte Gnanasara, is currently on bail after being arrested in May on a charge of insulting the Koran.
Sri Lanka, facing an international probe of its war record in crushing separatists Tamil rebels in may 2009, is also criticised for its alleged failure to protect minority religious groups.
Muslims make up about 10 percent of Sri Lanka's 20 million population, but are accused by nationalists of having undue influence.