"We looked at footage from three cameras and found that there was no conniving of troops with the rioters," Senanayake told reporters in Colombo.
"If there was any, I would not hesitate to take action."
He said the mobs included a lot of young men who were drunk.
However, he did not say where the controversial CCTV footage came from.
He added that soldiers had initially been outnumbered against hundreds of men armed with sticks and petrol bombs who attacked Muslim-owned businesses, homes and mosques.
The military has stepped up its presence in the worst affected North-Western Province to prevent a repeat of the violence, Senanayake said.
Some 5,500 additional police have also been deployed in the province.
"We are continuing search operations to arrest those responsible for the riots," he added.
Police said they had detained at least 112 suspects by Wednesday evening and more arrests were being carried out to ensure there was no repetition of the riots.
"We welcome the arrests made in connection with the violence, and call on the government to ensure that the rule of law is upheld and that the law is applied equally to all instigators and perpetrators of communal violence," a joint statement by the diplomats said.
A shopkeeper in Minuwangoda, one of the worst affected towns just north of Colombo, said roads were reopened Thursday amid a heavy military and police presence.
"I normally have about 30 customers in the morning, but today there were just three," the electronic goods seller told AFP by telephone. "Banks have opened, but it will take a few weeks before we get back to our normal routine." There were similar reports from other riot-scarred towns.
The Easter Sunday attacks on churches and upscale hotels claimed 258 lives and were blamed on local jihadists who pledged allegiance to the Islamic State group.
A state of emergency has been in place since the attacks and security forces have been given sweeping powers to detain suspects.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)