NEW DELHI - India has invited all the 10 leaders of the Association of South-east Asian Nations to attend the country's Republic Day celebrations which include a colourful parade that showcases India's military might and cultural diversity.

This is the first time that New Delhi is extending an invitation for the annual celebration, on January 26, to a regional grouping.

"The 1.25 billion people of India are keen to welcome the Asean leaders as our chief guests at India's 69th Republic Day Celebrations,'' said Indian Prime Minister Narendra Modi in his opening statement at Asean-India Summit in Manila on Tuesday.

Mr Modi has also invited the Asean leaders to a commemorative summit marking 25th anniversary of India's ties with Asean, to be held on Jan 25.

Singapore Prime Minister Lee Hsien Loong has accepted the invitation.

Ms Preeti Saran, a senior diplomat in the India's Ministry of External Affairs, said at a briefing that the Asean leaders had accepted the invitation and called it the "the high point" of summit discussions.

India's Republic Day is a colourful event that features marching contingents, dancers and floats from different states of the country. It includes a flypast of fighter jets and attack helicopters as the country showcases its latest weaponry.

The choice of a chief guest involves lengthy discussions within the government and an invitation is usually extended to a country that India considers key to its diplomacy.

This year's chief guest was Abu Dhabi's Crown Prince Mohammed bin Zayed Al Nahyan, while last year it was then-French President Francois Hollande. Former US president Barack Obama and Japanese Prime Minister Shinzo Abe have been among the other invitees.

Mr Modi has been trying to infuse new energy into what used to be called India's Look East policy which he has dubbed "Act East". He has placed greater focus on connectivity with India's east Asian neighbours.

At a talk in New Delhi earlier this month, Singapore's Minister for Foreign Affairs, Dr Vivian Balakrishnan, had urged India to engage more with Asean. Singapore has continued to be a champion of deeper India-Asean ties and has been key to helping India forge close ties with Asean.

Asean is India's fourth-largest trading partner with trade at US$76.53 billion (S$104 billion) in 2014 to 2015.