COLOMBO • Police in Sri Lanka have arrested a key figure from an extremist Buddhist organisation blamed for a series of hate crimes against Muslims that has drawn international censure.

The 32-year-old man from the radical Bodu Bala Sena (BBS), or Buddhist Force, is the first suspect to be arrested in connection with arson attacks against Muslims that have stoked religious tensions.

Police spokesman Priyantha Jayakody said investigations were continuing into 16 "major incidents" of arson since April that hit Muslim homes, businesses, mosques and a cemetery.

"We are taking a tough stand against such crimes," he told reporters.

Police were criticised for failing to bring the radical Buddhist group to heel by capturing its fugitive ringleader Galagodaatte Gnanasara, as the minority Muslim community endured attacks with stones and petrol bombs.

Mr Jayakody said the detained suspect is a close associate of Gnanasara, an extremist monk who has gone underground since late last month when he was ordered by police to turn himself in for questioning. Four specialist teams were hunting the BBS mastermind, he added.

The BBS says its leader is in hiding out of fear for his life. It has also denied orchestrating the latest violence against Muslims, who make up 10 per cent of the country's mainly Buddhist population.

The militant Buddhist outfit was accused of instigating religious riots in mid-2014 that left four people dead but escaped prosecution under then strongman president Mahinda Rajapakse.

Mr Rajapakse's brother Gotabhaya, a former defence secretary, was said to be close to the hardline Buddhist group.

The latest failure to stop a renewed outbreak of religious violence has seen the European Union and foreign envoys urge Sri Lanka to take action.

The EU delegation chief in Colombo, Mr Tung-Lai Margue, has said it was crucial there was "no impunity for hate crimes" and that the perpetrators are swiftly brought to justice.

AGENCE FRANCE-PRESSE