A “harsh and dangerous” crackdown on Sri Lankan Muslims following deadly bombings on Easter Sunday poses a major threat to the Indian Ocean nation’s peace and security, a think-tank has warned.

The assailants behind the church and hotel bombings in April were fringe actors, but politicians and Sinhalese nationalists have used the attacks to “justify actions that have harassed and humiliated the broader Muslim community”, the International Crisis Group (ICG) said in a new report on Friday.

The attacks, which killed more than 250 people, were claimed by the Islamic State of Iraq and the Levant (ISIL or ISIS). But Sri Lankan police said members of an offshoot of a local Muslim group, National Thowheed Jamath, were responsible.

It was the deadliest single day of violence in the country, which is still recovering from a bloody civil war with ethnic Tamil separatists, and the first experience of Muslim-on-Christian mass violence, the ICG said.

Since then, more than 1,800 Muslims have been arrested under emergency laws and nearly 300 remain in custody, it said. Muslims account for 10 percent of Sri Lanka’s Sinhalese Buddhist-dominated population.

Families of those arrested told the ICG that many of those imprisoned had no connections to the attacks, but had been reported to the authorities out of fear and bigotry.

Meanwhile, “Sinhalese Buddhist nationalists have waged a campaign of violence and hate, including economic boycotts, vigilante attacks on women wearing hijabs and media smear campaigns,” the report said.

“Two days of devastating riots targeting Muslim businesses and mosques in mid-May raised fears of an island-wide pogrom,” it warned. One Muslim was killed in the riots and scores of Muslim homes and Muslim-owned businesses were destroyed.

Anti-Muslim campaign

The anti-Muslim violence was not a spontaneous retaliation for the Easter attacks, the ICG said, but a continuation of a years-long campaign.

The attacks followed the same script as previous anti-Muslim riots, such as those in central Kandy last year, with Sinhalese nationalist groups bussing in supporters and security forces “failing to maintain order and in some cases appearing to assist rioters”, it added.

Sinhalese nationalist politicians and commentators have also seized the moment to “inject new energy into long-standing efforts to undermine the status and prosperity of the Muslim community”.

Gotabaya Rajapaksa, opposition presidential candidate and brother of former President Mahinda Rajapaksa, has made security a key focus of his campaign. Polls are expected later this year.

Some senior monks have also engaged in violent rhetoric against Muslims. In June, Ven Warakagoda Sri Gnanarathana Thera, one of Sri Lanka’s two senior-most Buddhist monks, supported the call for the boycott of Muslim-owned businesses and repeated unfounded rumours that a Muslim doctor has sterilised Buddhist women.

All the while, Sri Lanka’s weak and divided leadership “has either stood idly by or egged on the abuse”, the report said.

Despite the heavy pressure on the Muslim community, Prime Minister Ranil Wickremesinghe’s UNP-led government has said and done little to reassure the minority, the ICG said, partly because it fears losing Sinhala voters to the opposition.

“The Easter bombers succeeded thanks principally to the failures of the state, not the Muslim community,” the ICG said, noting foreign intelligence services had alerted Sri Lankan security agencies to such a threat weeks before the attacks.

“If Sri Lanka’s leaders want to avoid future attacks, they should focus their attention on repairing the state’s broken security apparatus and stop alienating law-abiding Muslim citizens.”