Sri Lanka's leader said Thursday that suspects in Easter Sunday's bombing attack that killed at least 253 people, including 30 foreigners, at churches and luxury hotels in the country were still at large and may be carrying explosives.
Prime Minister Ranil Wickremesinghe made the admission to The Associated Press as Sri Lankan security services issued a public appeal for three women and one man suspected of involvement in the Islamic State group-claimed attack.
Police identified the suspects as Mohamed Shahid Abdul Haq, Fathima Latheefa, Abdul Cader Fathima Kadia and Pulasthini Rajendran, who also had the alias Zara. All appeared to be in their 20s.
At least 58 people have been detained in connection with the bombings, among the world's worst terrorist attacks since 9/11, in which almost 3,000 people died.
Police revised down the death toll Thursday, citing chaotic bombing scenes.
Investigators have confirmed that nine suicide bombers took part in the assaults. They are all linked to National Thowheed Jamath, a local Islamist movement, but Sri Lankan officials believe they have "some links" to the Islamic State group, or ISIS.
Two of the suspected suicide bombers were the sons of a local spice tycoon while another spent time studying in the United Kingdom, which warned its nationals against all but essential travel to Sri Lanka amid the ongoing security situation. The State Department's travel advisory urges Americans to "exercise increased caution."
Burying the dead: Mass funerals begin after deadly Sri Lanka attacks
Sri Lanka's government has acknowledged that some intelligence units were aware of possible attacks weeks before the bombings Sunday, but that the information was not shared widely with other authorities, including the nation's prime minister.
The country's defense minister resigned Thursday.
Police officials in Sri Lanka have been warning of possible new attacks on religious services since Sunday. The U.S. Embassy in Sri Lanka on Thursday tweeted a warning to avoid "places of worship" this weekend over possible extremist attacks.
Security has been stepped up in Sri Lanka's capital Colombo and elsewhere across the island country, which is home to a complex web of multi-ethnic and multi-religious communities. About 70 percent of Sri Lankans are Buddhist.
For almost three decades, until 2009, the Tamil Tigers, a separatists militant organization, waged guerrilla warfare against Sri Lankan government forces. They were a majority-Hindu group but religion did not play a big role in their independence movement. The Tamils were among the first groups to use suicide bombers.
Wickremesinghe told the AP that Ahmadi Muslims, a refugee minority group from Pakistan, have faced apparent retaliation attacks since the Easter bombings. He said that some people "had become suspicious of foreigners, not of Muslims per se ... In the heat of the moment, a few have been attacked." Wickremesinghe said that Sri Lanka's security forces were giving Ahmadis police and military protection.
Mass funerals have been taking place in Sri Lanka since Tuesday.
Four Americans were killed in the attacks. They have been identified as Alex Arrow, 11, from Washington, D.C.; siblings Amelie Linsey, 15, and Daniel Linsey, dual American-British nationals who lived in London; and Dieter Kowalski, 40, from Denver.
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This article originally appeared on USA TODAY: Suspects in Easter Sunday bombings in Sri Lanka still at large, may be carrying explosives