Ruwan Wijewardena, the country’s defence minister, described the blasts as terrorist attacks by religious extremists, though no group has claimed responsibility for the violence.
Most of the explosions are believed to have been suicide bombings, which occurred at sites mainly in and around the capital of Colombo.
Officials said that 13 suspects had been arrested in connection to the attacks.
Three police officers were also killed while carrying out a security raid at a suspected safe house several hours after the blasts occurred.
At least five British citizens lost their lives in the attacks.
Citizens from the US, Turkey, Denmark, China and Portugal were also among the dead.
It is unclear when the curfew will be lifted.
Additional reporting by agencies
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