The investigators are trying to find out if the arrested people, Sri Lankans, are connected abroad, said the prime minister.

Eight people were arrested in Sri Lanka in connection with the wave of attacks on Sunday, killing at least 207 people, Prime Minister Ranil Wickremesinghe said.

"So far the names we have are local" but investigators are looking to find out if they have any "foreign links," said in a television speech the head of government, without giving further details.