In late May, President Sirisena told diplomats -- from Australia, Canada, Japan, the US and European states -- the security situation was '99 per cent back to normal' and he would allow the emergency laws to lapse by June 22.
After carrying out searches at seven locations in the city on Wednesday, the NIA had detained six people for questioning and arrested prime accused Mohammed Azarudeen, who was a Facebook friend of Sri Lankan Easter Day blasts mastermind Zahra Hashim.
External Affairs Minister Sushma Swaraj said India is open to ideas on how we can make the work of Regional Anti-Terrorism Structure (RATS), which specifically deals with issues relating to security and defence, more effective.
Efforts are on at the diplomatic level to get the two prominent members of the National Thawheed Jamath (NTJ), which carried out the Easter Sunday suicide attacks on April 21, arrested and deported to Sri Lanka.
"Considering the current situation in the country, we have reviewed the visas system and took a decision to tighten visa restrictions for religious teachers," Sri Lanka Home Affairs Minister Vajira Abeywardena said.
Investigations have revealed that Saharan Hashim, the main suspect in the serial blasts in Sri Lanka, used to follow the preaching of Naik.
The April 21 Easter Sunday bombings killed at least 250 people.
Shiv Sena alleged that many Muslims have not understood the true meaning of their religion (Islam), and have confused it with traditions and customs like burqa, polygamy, triple talaq and resistance to family planning.
The US Embassy in Colombo has said that at the request of the Sri Lankan Government, US security experts were working closely with their Sri Lankan partners on "fulfilling short term, specific objectives" related to the recent attacks and to bring the perpetrators to justice.
President Sirisena acknowledged during his meeting on Monday with the country's hoteliers, that the tourism and hotel industries were worst hit after the string of powerful blasts ripped through three churches and as many luxury hotels on Easter Sunday.
Mohamed Hashim Mathaniya, the sister of Mohamed Zahran Hashim, the man Sri Lankan authorities believe was one of the leaders of the attacks, said she identified her brother from photographs of his body parts at the police station earlier in the week.
The new regulation banning any form of face covering was announced a week after the coordinated blasts hit three churches and three luxury hotels, killing over 250 people and inuring more than 500 others in Sri Lanka