A Sri Lankan police spokesman also said there was a so-far unexplained explosion in a town east of the capital but there were no casualties. It was not a controlled detonation like other blasts in recent days and was being investigated, he said.
Sri Lankan authorities locked down the central bank and the road leading to the capital’s airport was shut briefly by a bomb scare. In the eastern part of the country, there was a powerful explosion.
The street outside the building near the World Trade Center in the capital, Colombo, was blocked to traffic before the security alert was lifted. The airport road was shut after a suspicious vehicle was identified at a nearby car park. The road was reopened when the alert was declared a false alarm.
Sri Lanka has banned drones and unmanned aircraft as authorities continue controlled detonations of suspicious items four days after a series of suicide bombing attacks killed more than 350 people in and around the capital of Colombo.
Police said on Thursday 16 more people were detained for questioning overnight, taking the number held since Sunday to at least 76. That number includes a Syrian national, an Egyptian and several Pakistanis in connection with the bombings, claimed by Islamic State. Sri Lankan Police said were among those detained.
Islamic State offered no firm information to back up its claim of responsibility. The Islamist group released a video on Tuesday that showed eight men, all but one with their faces covered, standing under a black Islamic State flag and declaring their loyalty to its leader, Abu Bakr al-Baghdadi.
Authorities said that a group of nine well-educated, home-grown Islamist suicide bombers, including a woman, who carried out the attacks on Easter Sunday.
Authorities have also focused their investigations on international links to domestic Islamist groups – National Thawheed Jama’ut and Jammiyathul Millathu Ibrahim – they believed carried out the attacks.
Sri Lankan officials have said they believed the bombings were carried out in retaliation for the March 15 attacks by a lone gunman on two mosques in New Zealand that killed 50 people.
New Zealand Prime Minister Jacinda Ardern has said she has seen no evidence to support that claim.
President Maithripala Sirisena will meet representatives of different faiths later on Thursday to address concerns of a sectarian backlash.
Muslims have fled the Negombo region on Sri Lanka’s west coast since scores of worshippers were killed in the bombing of the St. Sebastian church there on Sunday. Communal tensions have since flared.
Hundreds of Pakistani Muslims left the port city on Wednesday, crammed into buses, after threats of revenge.
Most of the Easter Sunday victims were Sri Lankans, although authorities confirmed at least 38 foreigners were also killed. These included British, U.S., Australian, Turkish, Indian, Chinese, Danish, Dutch and Portuguese nationals.