The treaty allows the three countries open new routes among themselves via converting the Iranian southeastern port of Chabahar into a transit hub.
In the first phase, India will invest about $200 million (approx Rs. 1,346 crore) to develop cargo berths and terminals, while a 500-kilometre railway line will be constructed between Chabahar and Zahedan - the capital city of Iran's Baluchestan province - in the second phase.
Reiterating the commitment to complete and operationalise the Port at the earliest, Radhakrishnan, along with Iranian Transport Minister Dr Abbas Akhoundi and Afghanistan Trade and Commerce Minister Humayoon Rasaw, reviewed and positively assessed the progress in the development of the Chabahar Port in the trilateral meeting.
Speaking on Sunday in Chabahar, Sistan and Baluchistan province, Dr Rouhani added: "This port has a special position and situation, which can shorten the North-South Corridor and connect it to the ocean".
According to the Indian Foreign Ministry's website, Chabahar Port was scheduled to be inaugurated by Rouhani on Sunday at presence of Ministers from India, Afghanistan and the region.
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The expansion, with $235 investment from India, has boosted the port's capacity from 2.5 million to 8.5 million tons a year. Chabahar provides India an easier land-sea route to Afghanistan.
It said that Zarif had referred to the Shahid Beheshti Port and said it reinforces mutual and regional cooperation between India and Iran. India has been closely working with Afghanistan to create alternative, reliable access routes, bypassing Pakistan.
The three sides also commended the recent joint efforts that led to the transit of first tranche of 110,000 tons of wheat from India to Afghanistan through Chabahar Port.
Ahead of the inauguration, External Affairs Minister Sushma Swaraj and her Iranian counterpart Javed Zarif held a meeting on Saturday in Tehran and discussed about the Chabahar port project among other issues.
The port will increase the capacity of loading and unloading of ships as well as the employment rate in the province, according to an official with the Sistan and Baluchestan Ports and Maritime Organisation.