Twenty-four Indians were on board 'Grace 1' seized by Gibraltar authorities. (Reuters photo)

India on Thursday said it was in close contact with Gibraltar to secure the release of 24 Indian crew on board a seized Iranian oil tanker.

External Affairs Ministry Spokesperson Raveesh Kumar said that the Indian Embassy in Tehran is also in touch with Iranian authorities for release of 18 Indians on board a British oil tanker seized by Iran's Revolutionary Guards.

On July 4, British marines helped Gibraltar in detaining Grace 1, the Iranian tanker, which was reportedly carrying oil to Syria in violation of sanctions slapped against the Gulf nation by the European Union.

Two weeks later, Iran seized a British oil tanker near the Strait of Hormuz, further escalating the tension between the two countries.

Twenty-four Indians were on board 'Grace 1' and 18 were on board British tanker Stena Impero.

Authorities in Gibraltar had granted consular access to the 24 Indians last week.

"We found them to be calm and composed. They are in touch with their family members...what we are doing simultaneously is that we are maintaining close touch with Gibraltar port authorities and the shipping company to ensure their release and repatriation," Mr Kumar said at a media briefing.

He said Indian mission in Tehran is also in touch with Iranian authorities to secure release of 18 Indians who were on board Stena Impero.