Modi was received by his Lankan counterpart Ranil Wickremesinghe at the Bandaranaike International Airport.
"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 SL in equal measure. India never forgets her friends when they are in need. Deeply touched by the ceremonial welcome," Modi tweeted soon after his arrival here.
In his brief visit to the island nation, Modi held discussions with President Maithripala Sirisena. This is Modi's third visit to Sri Lanka. Earlier, he visited the country in 2015 and 2017.
PM Modi pays respect at Easter Sunday terror attack site:
Prime Minister Narendra Modi on Sunday visited a Catholic church - one of the sites of the horrific Easter Sunday attacks - soon after his arrival here and paid tributes to the victims of the deadly terror strikes, saying "cowardly acts of terror cannot defeat the spirit of Sri Lanka".
Prime Minister Modi's entourage made a detour to St Anthony's church on their way to the Presidential Secretariat, where a red carpet welcome awaited.
"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," said Modi, the first foreign leader to visit Sri Lanka after the Easter attacks in April.
"My heart goes out to the families of the victims and the injured," Modi added.
IN PICS: PM Modi visits Easter Sunday terror attack site in Sri Lanka
Meeting with Sri Lankan President Maithripala Sirisena:
Prime Minister Narendra Modi met with Sri Lankan President Maithripala Sirisena on Sunday and the two leaders discussed bilateral issues of mutual interest.
"PM Narendra Modi and President of Sri Lanka Maithripala Sirisena, discussed bilateral issues of mutual interest. A banquet was hosted in honour of PM by President Maithripala Sirisena," External Affairs Ministry spokesperson Raveesh Kumar tweeted.
Ceremonial reception at President's House:
Earlier, Modi was accorded a ceremonial reception at the President's House. Sri Lankan President Sirisena was seen holding an umbrella and providing cover to himself and Prime Minister Modi from rain.
Modi arrived in Colombo from Maldives where he held wide-ranging talks with Maldivian President Ibrahim Mohamed Solih on Saturday.
Ahead of the visit, the External Affairs Ministry said that Prime Minister Modi is visiting the country with a very clear message of solidarity and signalling our confidence in the Sri Lankan government in overcoming the tragedy.
Asked whether India will help Sri Lanka deal with the scourge of terrorism, the ministry said on Thursday it was ready for any assistance to any country of the region.
Sri Lanka was hit by a wave of bombings on April 21. The attacks came despite prior intelligence warnings from India. Sri Lankan police said they have made elaborate security arrangements for the visit, including traffic movement restrictions during the day.
Modi arrived in Colombo from Maldives where he held wide-ranging talks with Maldivian President Ibrahim Mohamed Solih on Saturday.
"Dear citizens of the Republic of Maldives, I am humbled by the affection I have received in you wonderful nation. Thank you for being great hosts. I also thank the Government for the hospitality. This visit will lead to stupendous outcomes, adding vigour to bilateral ties," Modi tweeted.
During Modi's visit, the two countries signed six agreements to strengthen bilateral cooperation in key areas like defence and maritime security. A coastal surveillance radar system and a composite training centre for the Maldives defence forces were jointly inaugurated by Modi and Solih.
Modi was also conferred with the Maldives' highest honour "Rule of Nishan Izzuddeen" during his visit. He also addressed the Maldivian Parliament, the Majlis, an indication of India's important position in the neighbourhood. Giving a push to enhance connectivity, India and Maldives also agreed to start a ferry service from Kochi in Kerala to the Maldives.
His visit to Maldives and Sri Lanka demonstrates the priority that India attaches to the SAGAR (Security and Growth for All in the Region) doctrine, the sources said.
Ahead of leaving for the two countries, PM said: “ I am confident that my visit to the Maldives and Sri Lanka will further strengthen our close and cordial ties with our maritime neighbours, in line with our 'Neighbourhood-First Policy' and the vision of security and growth for all in the region.
In a pre-departure statement, he said his visit to Sri Lanka is to express India's solidarity with the government and the people of the island nation in the wake of the "terrible terrorist attacks" there on April 21.
"The people of India stand firmly with the people of Sri Lanka, who suffered great agony and destruction in the wake of the horrific terror attacks on Easter. We fully support Sri Lanka in the fight against terror," he said.
(With inputs from agencies)