The tiny island nation's Muslim minority continues to face discrimination since the deadly bombings in April.
Sri Lankan authorities have arrested hundreds of Muslims on flimsy charges since the deadly Easter Sunday bombings in April killed more than 200 people, a human rights group says.
The attacks blamed on radical terrorists have led to arbitrary detentions and arrests of Muslims in the country for reasons including possessing a Quran or other Arabic literature, says Human Rights Watch (HRW).
Police have held people under a notorious law - Prevention of Terrorism Act - which successive governments have abused in the past to keep ethnic Tamils in jail without due process.
HRW’s report comes as the Organisation of Islamic Cooperation (OIC), a group of 57 countries, expressed concern about attacks on Muslim-owned and places of worship by Buddhists.
“Sri Lankan officials and politicians should stop endorsing, ignoring, or exploiting hate speech and mob violence directed at Muslims by members of the Buddhist clergy and other powerful figures,” the HRW says.
Muslims, who make up around 9 percent of the population, had witnessed communal tensions in the past, such as the one last year when Buddhist radicals burnt several Muslim shops and homes.
The attacks followed what experts said was a security lapse as it was no longer a top priority for the law enforcement officials in the tiny island-state of 22 million people after the war between the majority Sinhalese and Tamil separatists ended in 2009.
The government says a little-known group called National Thowheed Jamath was behind the coordinated April attacks on churches and hotels.
The Jamath is seen as a Daesh affiliate, which was able to efficiently plan and execute the bombings because Sri Lanka no longer focuses on counter-terrorism as it did during the civil war.
The attacks also happened at a time when the Sri Lankan government of Prime Minister Ranil Wickremesinghe was struggling with a slowing economy that has struggled to pay off foreign loans.
In recent years the country has gone through political turmoil with Wickremesinghe's problematic relationship with President Maithripala Sirisena, who is from another party.
All this has left officials distracted.
In just two days of riots in May, Sinhala mobs went on a rampage killing one Muslim man, injuring over a dozen and destroyed more than 500 Muslim-owned houses and businesses. All that happened while a state of emergency was in place.
HRW says instead of protecting the Muslim minority, government officials are cosying up to Buddhist nationalists.
Gnanasara Thero, a Sinhalese Buddhist extremist, who has regularly made anti-Muslim speeches, was released on a presidential pardon in May without even completing a year of a 6-year long term, HRW says.
“Officials have made little effort to discourage public campaigns by religious figures that put the Muslim community at greater risk.”
President Sirisena has also ordered a ban on face coverings in public, which has led to the targeting of Muslim women even for using headscarves, the report says.
The growing government indifference came into stark view last month when eight Muslim government officials resigned in solidarity with the Industry Minister Rishad Bathiudeen who was accused of having links with one of the bombers.