Indian shipping officials say all 21 Indian crew members of a chemical oil tanker held hostage by Somali pirates since August have been released.

An Indian shipping spokesman said late Saturday the crew and the ship, the MV Fairchem Bogey, are heading towards a safe port. He did not give any details of the release, including whether a ransom was paid.

The Marshall Islands-flagged vessel was hijacked August 20 when it was anchored at Salalah port in Oman.

The shipping official said Saturday 22 Indian sailors remain held by Somali pirates on various ships in the Indian Ocean.

Piracy for ransom is an organized and lucrative operation in Somalia that has expanded into a vast area off the country's coast.

International naval forces are patrolling the waters near Somalia. Shipping companies have increasingly taken security measures to prevent hijackings, such as posting armed guards on board, and building “safe rooms” in which crews can lock themselves if pirates board their ships.