Tehran/New Delhi, Sep 6 (IANS): Indian oil tanker MT Desh Shanti, carrying 140,000 tonnes of Basrah crude from Iraq to India, continues to stay at Iran's Bandar Abbas port after it was detained by Iranian authorities last month for allegedly causing pollution.

“The tanker is still in Iran,” an Indian official told IANS in New Delhi.

Iran's Ports and Maritime Organization chief Ataollah Sadr said the Indian oil tanker can leave the country after “presenting the necessary guarantees to the Iranian Ports and Maritime Organization and compensating through its protection and indemnity (P&I) insurance coverage”, said Iran's Fars News Agency.

The Shipping Corp of India (SCI) vessel was detained Aug 12 in the Persian Gulf.

Nima Pourang, director general for maritime pollution affairs at Tehran, told Fars that the tanker has been detained because it discharged its oily ballast water 30 miles away from Iran's Lavan island in the Persian Gulf which caused a 10-mile-long oil slick on the sea.

Iranian foreign ministry spokesman Seyed Abbas Araqchi has rejected media reports that the move was politically motivated. India has slashed its oil imports from Iran following US and EU sanctions on Tehran for its alleged nuclear weapons programme.

"The ship has been detained by Iranian naval forces for causing widespread pollution in the Persian Gulf," Araqchi said, adding that the inspection of the Indian tanker was not at all due to political reasons.

The supply of crude from Iran slipped from 18.1 million tonnes to 13.3 million tonnes in 2012-13, a fall of about 26.5 percent.

On Aug 28, India decided to lodge a strong protest over the detention of its oil tanker and sought an "unconditional" release of the vessel. Foreign Secretary Sujatha Singh summoned Iranian Ambassador Gholamreza Ansari to lodge the protest.