"I am confident Sri Lanka will rise again. Cowardly acts of terror cannot defeat the spirit of Sri Lanka. India stands in solidarity with the people of Sri Lanka," Modi tweeted as he began a packed one-day visit to the island nation.
Modi, who arrived here from the Maldives and was ceremonially received by Prime Minister Ranil Wickremesinghe, began his Sri Lanka visit by going to one of the sites of the Easter Sunday attack, the St Anthony's church.
"My heart goes out to the families of the victims and the injured."
Modi is the first foreign leader to visit Sri Lanka after the horrible terror attack of April 21 that killed over 250 people and which was blamed by Colombo on a Sri Lankan Islamist outfit although the mayhem was claimed by the Islamic State.
The Indian Prime Minister's Office described Modi's visit as "important, signifying the strong bonds of friendship with a valued neighbour".
On his part, Modi tweeted after his welcome ceremony: "Happy to be back in Sri Lanka, my third visit to this beautiful island in four years.
"Share the warmth shown by the people of Sri Lanka in equal measure. India never forgets her friends when they are in need. Deeply touched by the ceremonial welcome."
After becoming the Prime Minister, Modi earlier visited Sri Lanka in March 2015 and May 2017.
Modi is scheduled to hold talks with Sirisena. Later, the Leader of the Opposition Mahinda Rajapakse, a former President, and a delegation of the Tamil National Alliance (TNA) will call on the Indian leader.
Before returning to New Delhi, Modi will offer prayers at the Tirupati shrine.
India is Sri Lanka's largest trading partner globally, and it also accounts for the largest FDI in the island nation.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)