Police spokesman Ruwan Gunasekara said earlier that the violence was brought under control and two people arrested.
"Elections can not be postponed, therefore before the elections I will bring about stability and I will eradicate terrorism", he said.
The elections are likely to take place between November 10 and December 10.
The Sri Lankan authorities suspect that the blasts were carried by a splinter group of the local islamist group National Thowheed Jama'ath.
"Therefore please avoid hurting them and try to create a better spirit of understanding and good relations between all the communities of Sri Lanka", he said in a video message to the island country. The official was quoted by HT saying that when a threat call is received, a bomb threat assessment committee is formed which categorises the threat into specific or non-specific threat based on which, every part of the airport is put on alert.More news: Donald Trump rips Kentucky Derby result, blames 'political correctness'
Sri Lankan Army Commander Major General Mahesh Senanayake has said the terrorists involved in the Easter Sunday bombings in Colombo were trained in India.
Cardinal Malcolm Ranjith made the declaration in a letter dated Thursday that was sent to church officials. "It will be like last Sunday when we had a service at Archbishop's chapel and telecast it live", Tillakaratne said. "I appeal to all Christians, Buddhists and Muslims to be patient, show restraint and ensure the peace we maintained after the Easter bombings", he said.
The training camp was found in a residential area for the poor located on the outskirts of the hometown of Zahran Hashim, who is believed to be one of the main plotters of the Easter Sunday terror attacks.
Catholic schools have also been closed until further notice.
The Easter attacks targeted three luxury hotels and three churches, including St. Sebastian's Church in Negombo. Prime Minister Ranil Wickremesinghe said on Friday that some of the conspirators may still be at large.
In connection with the investigations, Sri Lankan authorities announced the expulsion of 600 foreigners, including 200 Islamic clerics. About 50 children were among those killed.
The police said in a statement that anyone possessing illegal weapons could hand it over to their nearest police station on Monday and Tuesday and urged the public to corporate.