COLOMBO, Sri Lanka — A gun battle erupted as Sri Lankan security forces raided a house in search of suspects linked to the Easter Sunday bombings, and four people inside detonated explosives as the authorities closed in.
The security forces said they found the bodies of 15 people inside on Saturday, including six children. A woman and child, both seriously wounded, were evacuated from the house and taken to a hospital, the army said.
The house in the village of Bolivarian on Sri Lanka’s east coast was cordoned off after the overnight raid. But security forces waited until dawn to search it because it is in a crowded neighborhood.
Bolivarian is part of the densely populated, mostly Muslim town of Sainthamaruthu. It is about 25 miles from Batticaloa, where one of the church bombings took place.
A man who lives in the area said members of the local mosque federation, to which he belongs, had become suspicious about the tenants in the house, which he said was twice the size of many others in the area. He said two members of the federation asked the tenants to identify themselves on Friday afternoon. The tenants said they did not have identification with them, but promised to provide it the next day, he said.
Members of the mosque federation returned in the evening with a local official, said the man, who asked not to be identified because he feared for his safety. As they approached the house from the back, the first explosion occurred, said the man, adding that the bombers might have suspected that someone was coming for them.
The man, who was at home when the first blast happened, said he then heard continuous gunfire and another explosion. He saw people running, including a police constable. About 30 minutes later, he said, security personnel arrived in force.
Another house a few miles away was also raided on Friday. The army said troops there found Islamic State flags, suicide kits, military uniforms and explosives with detonators.
The raids began just hours after President Maithripala Sirisena promised a house-to-house search of the entire country and a “total reorganization” of Sri Lanka’s security apparatus. His government is under enormous pressure for failing to act on repeated warnings that attacks on churches were being planned.
“Every household in the country will be checked,” Mr. Sirisena said in a meeting on Friday, according to a statement released by his office. “The lists of permanent residents of every house will be established to ensure no unknown persons could live anywhere.”
The country continued to remain on high alert, as security forces arrested dozens more people — on top of the 70 whom Mr. Sirisena said had been arrested by Friday. Among those arrested on Friday was a man believed to be the driver of the attack’s suspected mastermind, Zaharan Hashim, and a deputy mayor of Negombo, local news media reports said.
In parts of the eastern coast, a curfew has remained in place since Friday afternoon. In Colombo, the capital, where a curfew was due to go into effect again at 10 p.m. Saturday, most of the streets were emptying early in the evening, on what would otherwise be a busy night. Shopping malls and coffee shops began closing around sunset, while many restaurants and bars remain closed.
Frustration and fear have continued to grip Sri Lanka since the Easter bombings, particularly in Colombo, as officials have warned that other potential bombers could still be on the run and plotting attacks.
Sri Lankan security officials wrote a memo 10 days before the bombings warning that attacks were being planned, including names, addresses and phone numbers of people believed to be involved, but the president and prime minister have said the memo never reached them. Foreign intelligence agencies had repeatedly warned that attacks were being planned, with one such warning coming just hours before the bombings.