Sri Lanka's president is banning two groups allegedly linked to the Easter bombings under emergency powers that came into effect on Tuesday.

The office of President Maithripala Sirisena said in a statement Saturday evening that National Thawheed Jammath, or NTJ, and Jamathei Millathu Ibraheem, or JMI, would be banned by presidential decree.

Presidential spokesman Dharmasri Ekanayake says the move allows the government to confiscate any property belonging to the two organizations.

On Monday, officials confirmed that the alleged leader of the Muslim extremist group, an offshoot of NTJ, had died in one of the coordinated suicide bombings at churches and hotels that killed more than 250 people.

The Islamic State group, meanwhile, claimed three of the militants who blew themselves up during a bloody police raid in Ampara linked to the Easter bombings.

In a statement carried by the extremists' Aamaq news agency, IS identified the bombers by their noms du guerre as Abu Hammad, Abu Sufyan and Abu al-Qa'qa. It said they opened fire with automatic weapons and "after exhausting their ammunition, detonated ... their explosive belts."

Sri Lanka's military said the gunfight Friday night near the town of Sammanthurai left 15 dead, including six children, when militants opened fire and set off explosives in suicide bombings as security forces closed in on their safe house.

IS falsely claimed their militants killed 17 "disbelievers" in the attack. The militants often exaggerate their claims.

The IS report carried a photograph of two men before an IS flag, one carrying a Chinese variant of the Kalashnikov rifle like the one found at the scene, another smiling.

A girl and a woman survived the explosion but were critically injured and being treated at a hospital, police spokesman Ruwan Gunasekara said.

Photographs taken by The Associated Press show the charred remains of one child and the body of another wearing a green T-shirt with the words "good boy" written on the back. The bodies of an adult woman and man were found after the explosion with their clothes burned off.

The military said security forces had recovered explosives, detonators, "suicide kits," military uniforms and IS flags during the raids in the area.

Gunasekara said officers acting on information from intelligence officials also found 150 sticks of blasting gelatin and 100,000 small metal balls, as well as a van and clothing suspected of being used by those involved in the Easter attacks on three churches and three luxury hotels that left more than 250 people dead and hundreds injured —the bloodies assault linked to the IS in South Asia.

The government on Saturday formally banned two extremist groups purportedly connected to the attacks, allowing officials to confiscate their property, presidential spokesman Dharmasri Ekanayake said.

The government, crippled from a long political crisis between the president and prime minister last year, promised swift action to capture militants still at large.Sirisena said about 140 people had been identified as having links to the IS.

A "major search operation has been undertaken," Sirisena said. "Every household in the country will be checked."

Police confirmed that the leader of the local militant group blamed for the attack, Mohamed Zahran, died in the suicide bombing at the Shangri-La Hotel, one of six hotels and churches attacked. Zahran appeared in an IS video claiming responsibility for the coordinated assault, and authorities in both Sri Lanka and Australia confirmed links between IS and the attack.

Sri Lanka is majority Buddhist but has significant Hindu and Muslim populations. About 7% are Christian, and most are Roman Catholic.