The crew of a UAE-owned suezmax has appealed for help after spending six months under detention in Egypt.
The 31 men on board the 163,000-dwt Sea Shark (built 1991) contacted Russian news agencies to highlight their plight.
AIS data shows the vessel sailed from Kharg Island in Iran in October to Suez.
There it awaited instructions from the shipowner, the TASS news agency said.
A crew representative told TASS: "For safety reasons, the ship accidentally went a couple of miles" into the territorial waters of Egypt "so as not to block the traffic of other vessels.
"For this reason, we were arrested, demanded to be followed by the Egyptian military ship."
Egypt is reportedly demanding $56m from the shipowner.
The crew need medical assistance, it has been reported.
”According to the embassy of Ukraine in...Egypt, a member of the crew of the Sea Shark vessel got into contact with the diplomatic office and reported that the vessel had been detained by the authorities of Egypt for violating the border of Egypt,” director-general for consular service at Ukraine's ministry of foreign affairs Serhiy Pohoreltsev told the UNIAN news agency.
On 25 April, the tanker moved from the port of Berenice to another Egyptian port, Ein El Sokhna, where the replacement of crew members was to take place.
The crew claim they were then ordered by the Egyptian military prosecutor's office to unload the crude over an alleged environmental threat.
"The crew members consider the decision of the prosecutor's office illegal and refuse to execute it, and representatives of Egypt's navy, for their part, do not give permission to replace the crew until the oil is unloaded from the ship,” Pohoreltsev said.
The ship is owned by Al Safeena Al Bahria Shipping, which has been contacted for comment.
Also on board are two men from Crimea in Russia, an Azerbaijani and 11 Filipinos, Sri Lankans and Indians.
