NEW DELHI (PTI): The first Indo-US tri-services exercise is likely to take place next year and talks are on to include the special forces of two countries in the drill, a senior US defence official has said.

The three forces of India and the US already take part in bilateral exercises separately -- their armies participate in an annual drill called Yudh Abyaas, whose latest edition took place last month, the air forces take part in a bilateral drill called Cope India and the navies participate in an exercise in Malabar, involving Japan.

But this will be the first time the three services of the India and the US will participate in a drill together.

"The first one will be in India, and it will take place in 2019. It would include all our services, plus we are kind of scoping the exercise right now to include each of the services' special operations forces. That's very exciting. This is under discussion right now...essentially all our services, plus potentially the special operations forces," Brigadier General David E Brigham told PTI.

An Initial Planning Conference (IPC) will be held to discuss the scale of the exercise, he said. No date has been fixed for the joint drill yet, he said.

The drill may take place somewhere in late August because US naval ships could be in the region around that time.

The drill will focus on United Nations-based scenario and the over-arching mission of humanitarian assistance, disaster relief measure, Brigham said.

He said India was the "natural humanitarian disaster relief hub" in the Indo-Pacific.

The Indian Army has Para SF, the Navy has Marcos while the Air Force has the Garud as their respective special forces.

Although the joint tri-services drill was formally announced after the first 2 plus 2 plus dialogue between the principals of the external affairs and defence ministries of the two countries last month, work on it had begun much before.