"The Prime Minister landed in Kathmandu a short while ago. He will be taking part in the Bimstec Summit being held in the city," Modi's office tweeted around 9 a.m.

Ahead of his departure, Modi on Wednesday said that his participation in the event symbolises the priority India accords to deepening ties with India's extended neighbourhood in Southeast Asia.

"My participation in the Summit symbolises India's highest priority to our neighbourhood and our strong commitment to continue deepening our relationship with the extended neighbourhood in Southeast Asia," he said in a pre-departure statement in New Delhi.

"During the Summit, I will have interactions with all the leaders of Bimstec (Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation) to further enrich our regional cooperation, enhance our trade ties and advance our collective efforts to build a peaceful and prosperous Bay of Bengal region," he said.

Bimstec came into existence on June 6, 1997, through the Bangkok Declaration.

It comprises seven countries lying in the littoral and adjacent areas of the Bay of Bengal -- Bangladesh, Bhutan, India, Myanmar, Nepal, Sri Lanka and Thailand.

The bloc brings together 1.5 billion people, or 21 per cent of the world's population, and has a combined GDP of $2.5 trillion.

The main objective of Bimstec is technical and economic cooperation among South Asian and Southeast Asian countries along the rim of the Bay of Bengal.