Iran has released nine of 12 Indian crew members from a Panama-flagged oil tanker detained on July 14, India said on July 26.
Tehran had accused the MT Riah ship of fuel smuggling when it was seized, amid rising tensions between Iran, Britain, and the United States over shipping in the Strait of Hormuz that connects the Persian Gulf and the Arabian Sea.
Twenty-one other Indian nationals remain in Iranian detention, including three from the MT Riah and 18 from the British-flagged Stena Impero tanker which was seized by Iran last week.
The Stena Impero and its 23 crew members have been impounded at the southern port of Bandar Abbas for allegedly breaking "international maritime rules." The tanker is the object of the dispute between Iran and Britain.
Three Russians, a Latvian, and a Filipino are also on the vessel.
India announced on July 25 that its diplomats in Iran had been allowed access to the Stena Impero crew.
Meanwhile, Iranian state media said on July 26 that Oman will act as a mediator in the row between Britain and Iran.
The foreign ministers of Oman and Iran, Yusuf bin Alawi bin Abdullah and Javad Zarif, are to meet in Tehran on July 27, the IRNA news agency reported.