The shootout between troops and suspected Islamist militants had erupted on Friday evening in Sainthamaruthu in Ampara district (Getty Images)

The bodies of 15 people, including six children, were discovered at the site of a fierce overnight gun battle on the east coast of Sri Lanka, a military spokesman said on Saturday (27), six days after suicide bombers killed more than 250 people on the island.

The shootout between troops and suspected Islamist militants erupted on Friday (26) evening in Sainthamaruthu in Ampara district, to the south of the town of Batticaloa, site of one of the Easter Sunday blasts at three churches and four luxury hotels.

A police spokesman said that three suspected suicide bombers were among the 15 dead after the shootout.

Islamic State claimed responsibility for last Sunday’s attacks, all but one of which were in the capital, Colombo. The government has said they were carried out by nine well-educated Sri Lankans, eight of whom have been identified.

Authorities have warned there could be more attacks targeting religious centres following the bombings, which shattered the relative calm that Buddhist-majority Sri Lanka had enjoyed since a civil war against mostly-Hindu ethnic Tamil separatists ended a decade ago.

The US State Department, warning that terrorist groups were continuing to plot attacks, urged citizens to reconsider travel to Sri Lanka.

It ordered the departure from the country of all school-age family members of US government employees and also authorised non-emergency employees to leave, it said in a statement.

Britain has also warned its nationals to avoid travelling to Sri Lanka unless absolutely necessary.