The 2,230-kg South Asia satellite - it weighs as much as four full grown elephants - will provide telecommunication links between India, Nepal, Bhutan, Bangladesh, Maldives, Sri Lanka and Afghanistan. Pakistan has opted out of the project.

PM Modi said it was a "journey to build the most advanced frontier in our partnership," and that "Our coming together is a sign of our unshakeable resolve to place the needs of our peoples in the forefront."

Heads of state of the participating nations thanked India via speeches on video conference. South Asia has moved from merely talking about regional integration to actually doing it, said Afghan President Ashraf Ghani.

Bhutan's Tshering Tobgay called it a generous gift by India and an example of true friendship, saying,"Satellite-based communications have now become the norm the world over. This will be especially beneficial for countries like Bhutan which cannot afford their own."

Praising India's "neighbour first policy", the heads of the neighbouring countries thanked PM Modi for the "gift" and said "it (the launch) will bring common progress of our region".

Today's launch is seen as a move to counter China's space diplomacy in the region. China has helped Pakistan and Sri Lanka launch communication satellites.

About 50 of India's best space engineers and scientists of the Indian Space Research Organisation (ISRO) monitored the launch of the South Asia satellite, which will help the countries communicate better during disasters and could help establish a hotline between them. It will also help in telemedicine and education.

The South Asia Satellite, which uses a new propulsion system, was built over three years. Its mission life is 12 years. The GSLV rocket that launched it weighs 414 kg and is 50 metres tall. This was the 11th flight of the GSLV, called the "naughty boy" by scientists.

PM Modi had, after taking office in 2014, asked scientists at ISRO to develop a SAARC satellite as a gift dedicated to neighbouring countries.