Iranian oil tanker "Adrian Darya 1" is seen in the British territory of Gibraltar, August 17, 2019. (Photo: IC)

ATHENS, Dec. 13 (Xinhua) -- Three crew members of a Greek-flagged tanker who were kidnapped by pirates off the coast of Togo on Nov. 4 were released, the tanker's manager announced on Friday.

The fourth abducted crew member, a Philippine national, has died during captivity, according to the press release issued by the European Products Carriers Ltd., manager of the oil tanker "Elka Aristotle."

"A full investigation is underway into the situation, but it is understood that his demise was not as a result of any actions by those holding the crew hostage, but due to illness," it noted.

The release three hostages "are safe and well, have had medical checks and are currently being debriefed by the local authorities prior to returning home to the Philippines, Greece and Georgia respectively," read the press statement.