Sri Lankan police reportedly issued a warning to top officials 10 days before a series deadly blasts struck churches and hotels in multiple cities across the country.

The country's police chief identified a known radical Muslim group as "planning to carry out suicide attacks targeting prominent churches."

Eight blasts were reported to have killed at least 207 and injured 450 people Sunday as worshippers across the country attended Easter Sunday mass.

Authorities said seven people were arrested Sunday in connection to the attacks after a house raid.

Sri Lankan police issued a warning to top officials 10 days before a series of deadly blasts struck churches and hotels across the country, according to intelligence reported by AFP.

Police chief Pujuth Jayasundara reportedly wrote in the intelligence alert that suicide bombers affiliated with a radical Muslim group planned to hit "prominent churches."

"A foreign intelligence agency has reported that the NTJ (National Thowheeth Jama'ath) is planning to carry out suicide attacks targeting prominent churches as well as the Indian high commission in Colombo," the alert reportedly said.

The National Thowheeth Jama'ath, or the NTJ, is a known group in Sri Lanka that was previously linked to the vandalization of Buddhist statues, the report notes.

Eight blasts were reported to have killed 207 people and injured at least 450 in churches and high-end hotels including the Shangri La, Cinnamon Grand, and Kingsbury.

Police spokesman Ruwan Gunasekera said seven people were arrested in connection with the bombings after a house raid in Colombo, a capital city.

Read more: At least 207 people killed in Sri Lanka after churches and luxury hotels hit by explosions

Though a 2012 census found Christians only make up 7.6% of the country's total population, they have been involved in the country's struggle amid religious tensions.

US State Department said in a 2018 report on the country's human rights that some Christian groups and churches reported they had been pressured to end worship activities after authorities classified them as "unauthorized gatherings."

This is the first major attack in nearly 10 years, or since the end of the civil war, which ended with the defeat of the Tamil Tigers. Years of intermittent violence followed.

The Muslim Council of Sri Lanka tweeted to condemn the attacks "on our Christian brothers and sisters on their Holy Day of Easter," that cost "innocent lives due to extremist and violent elements who wish to create divides between religious and ethnic groups to realize their agenda."

Sri Lankan officials were also quick to condemn the apparently coordinated attacks on worshippers, with Finance Minister Mangala Samaraweera calling the blasts "a well-coordinated attempt to create murder, mayhem & anarchy."

Sri Lankan Prime Minister Ranil Wickremesinghe tweeted to condemn the attacks, and also encouraged Sri Lankans to avoid spreading "unverified reports and speculation" as officials gathered to form a response to the attacks.

"I call upon all Sri Lankans during this tragic time to remain united and strong," Wickremesinghe wrote. "Please avoid propagating unverified reports and speculation. The government is taking immediate steps to contain this situation."

Tom Murray contributed reporting.