India and Russia were expected to sign the S-400 contract during Indian Defence Minister Nirmala Sitharaman visit to Moscow, however, a military-diplomatic source told TASS although all the technical parameters of the contract have been fully agreed, the sides have not yet agreed on the price of the deal. “The sides are continuing the negotiations on this sole issue that has not yet been agreed and there are no doubts that the document will be signed shortly,” the source noted.