Speaking further, the president said the Defence Secretary and Inspector General of Police had failed in their duties and that is why he called for their resignation.
He said that they had failed to share prior information obtained by them over a possible terror attack in the country.
The president added that he and the entire Government will also take the full responsibility for the attacks.
Inspector General of Police Pujith Jayasundara and defence secretary Hemasiri Fernando have resigned from their posts over the security establishment's alleged failures which led to the attacks on three hotels and three churches on Sunday.
"The IGP has resigned. He has sent his resignation to the acting defense secretary. I'll nominate a new IGP soon," the president said.
The police chief's resignation came a day after the country's defence secretary Hemasiri Fernando handed over his resignation letter to the president.
Nine suicide bombers carried out a series of devastating blasts that tore through three churches and three luxury hotels on Easter Sunday.
The Islamic State group has claimed responsibility for the attacks, but the government has blamed a local Islamist extremist group National Tawheed Jamath (NTJ) for the attacks.