Seven suspects have been arrested after the explosions injured up to 500 people, and the country's foreign minister said at least 27 foreigners were among those killed. Earlier reports indicated that nationals from the UK, US, Netherlands and Portugal were among the dead.
After an initial six blasts hit three churches and hotels - mostly concentrated near the city of Colombo - a further two were reported later in the day, killing 207 people, a police spokesperson said.
Britain's High Commissioner to Sri Lanka James Dauris said: 'We understand that some British citizens were caught in the blasts but we are unable to say how many people are, or might have been, affected.'
Sri Lanka's defence ministry has now ordered curfew with immediate effect 'until further notice', and the Sri Lankan government said it had shut down access to social media messaging services, sources say.