India on Thursday said it was vigorously pursuing the release of its oil tanker detained by Iran on Bandar Abbas port on August 13.
The Indian Foreign Ministry said "Regarding this incident of the Indian ship, we have constantly been in touch with Iran on this issue, and despite intensive discussions, we have not yet made any progress.
"The matter is being pursued vigorously by our Embassy in Tehran, and we would like to seek your patience as we work towards a successful outcome in a delicate situation," it added.
The oil tanker, MT Desh Shanti, belonging to the Shipping Corporation of India (SCI), was detained by the Iranian Revolutionary Guards from the international waters in the Persian Gulf ten days ago, government sources said.
The vessel was carrying 140,000 tonnes of Basrah crude oil from Iraq to India, they added.
The reports pouring from Iran suggest that ship was forcibly anchored at the port on environmental concerns, and the oil tanker discharged its oily ballast water 30 miles away from Iran's Lavan Island in the Persian Gulf, causing a 10 mile long oil slick in the sea.