While the new extension opens up a strategic transit route from India to Afghanistan and Central Asia - bypassing Pakistan - the Iranian government has reportedly asked India to "manage" or operate the first phase of the port, till the work for the second phase is finalized. Ahead of the inauguration, India's External Affairs Minister Sushma Swaraj on a surprise stopover in Tehran met her Iranian counterpart Javed Zarif on Saturday and discussed the Chabahar port project among other issues.
Earlier a year ago, the Indian government committed to invest up to $500 million for the development of the Chabahar port and other roads and rail lines associated with it.
According to Iranian state media, the inauguration of the port was attended by delegates from 27 countries.
Lying on the coast of the Gulf of Oman in Iran's southeastern Sistan-Baluchestan Province, Chabahar is the country's only oceanic port and given its strategic location in the International North-South Transport Corridor (INSTC), development of the port is of high significance for Tehran.
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In late October, India shipped its first consignment of wheat to Afghanistan from the western Indian port of Kandla. "We welcome other ports in the region, we welcome Gwadar's development".
US Secretary of State Rex Tillerson during talks in New Delhi last month said America would not stand in the way of projects that help the Iranian people. Chabahar provides India an easier land-sea route to Afghanistan.
Shahid Beheshti Port will be regarded as a new development stage for the province, Rouhani said, adding that the capacity of the port is 8.5 million tons. India has been closely working with Afghanistan to create alternative, reliable access routes, bypassing Pakistan.
Ahead of the inauguration, External Affairs Minister Sushma Swaraj met her Iranian counterpart Zarif in Tehran on Saturday, during a surprise stopover on her way back from a Shanghai Cooperation Organisation meeting in Russian Federation, and discussed the port project among other issues. The $340 million project is also expected to make Chabahar, Iran's closest sea link to the Indian Ocean, a rival to Gwadar Port, some 80 km away (50 miles) across the border in Pakistan, which Pakistan has been building with Chinese investment.