Iran is yet to release three Indian sailors on board a tanker it had seized (Reuters)

Iran has freed nine Indian crew members of a Panama-flagged tanker it seized this month, the Foreign Ministry said today, and it appealed for the release of three remaining crew members held from the same ship.

Dozens of Indian crew members on ships in the Gulf have been caught up in rising tensions between Iran and the West.

The MT Riah was detained by the Iranian coastguard on July 13, with 12 Indian crew members on board, the Foreign Ministry said.

"Nine crew members have been released and they will be on their way to India soon," Foreign Ministry spokesman Raveesh Kumar said.

"Our mission in Iran has requested the concerned Iranian authorities for the release of remaining crew members."

No reason was provided as to why the three were being held.

Iranian state TV aired footage of the vessel a few days after it was seized, saying it had been detained by Iran's elite Revolutionary Guards for smuggling fuel.

Indian and Iranian authorities said this week Iran had granted India consular access to 18 Indian crew seized on another ship, the British-flagged Stena Impero, that Iran seized in the Strait of Hormuz on July 19.

The seizure of the British tanker in the world's most important waterway for the oil trade has deepened a crisis between Iran and the West that was triggered in May when the United States tightened sanctions, effectively barring all countries from buying Iranian oil.

Iran said it had seized the Stena Impero because it had collided with a fishing boat.

Junior Foreign Minister V Muraleedharan said India was pushing for the release of the Indian crew on the British vessel. India has had long-standing political and energy ties with Iran, but it has cut off all its oil supplies from it because of US sanctions.