Colombo:Defence Secretary Hemasiri Fernando on Thursday resigned accepting responsibility for the Easter Sunday bloodbath in Sri Lanka even as security forces continued a search for accomplices of the suicide bombers who killed and injured hundreds.
The government also banned the use of all drones and unmanned aircraft within the Sri Lankan airspace with effect from Thursday and also kept its new visa-on-arrival programme, which was to be implemented from May 1, on hold due to the security situation in the island nation.
Fernando said after submitting his resignation that while there was no failure on his own part, he was taking responsibility for the failures of some institutions which were under his command.
President Maithripala Sirisena, who himself has come under attack from the opposition for failing to prevent the mass killings, had earlier asked the Defence Secretary and the police chief to quit.
Tourism, Wildlife and Christian Religious Affairs Minister John Amaratunga said that investigations had revealed foreign links to the attacks and the government did not want the visa-on-arrival facility to be abused.
Tourism was one of the worst hit industries following the deadly blasts on Sunday in three Sri Lankan cities, primarily in and around Colombo.
The Islamic State has claimed responsibility for the deaths of 359 people and injuries to over 500 but Colombo has blamed a local Muslim group, the National Thowheed Jamath (NJT).
The Sri Lanka Police released photographs of six young suspects - three males and three females - wanted in connection with the bombings. The Criminal Investigation Department (CID) sought public assistance to trace them.
The six were identified as: Mohammad Ivuhaim Sadiq Abdul Haq, Mohammed Ivuhaim Shaid Abdul Haq and Mohammed Casim Mohammed Rilwan (all men) and Fatima Latif, Pulasthini Rajendran alias Sarah, Abdul Cader Fatima Kadir (all women).
It was not clear if the six were linked to the National Thowheed Jamath.
On Thursday, security forces set up checkpoints and stepped up random checking of vehicles across Sri Lanka.