A series of explosions hit churches and luxury hotels in Sri Lanka's capital, Colombo, on Easter Sunday.
A police official told AFP that at least 156 people have been killed.
Scores of people have also been injured.
Near-simultaneous bombings took place in three Catholic churches and three hotels, followed by a fresh blast at another hotel.
According to reports, there are at least 35 foreigners among the dead.
Sri Lanka's Minister of Economic Reforms and Public Distribution, Harsha de Silva, said emergency operations are under way and appealed to people to stay indoors.
The country's prime minister, Ranil Wickremesinghe, denounced the attacks as "cowardly".
I strongly condemn the cowardly attacks on our people today. I call upon all Sri Lankans during this tragic time to remain united and strong. Please avoid propagating unverified reports and speculation. The government is taking immediate steps to contain this situation.— Ranil Wickremesinghe (@RW_UNP) 21 April 2019