PRETORIA, October 31./ TASS /.Somali pirates set free seven Indian sailors, who were held hostage for four years, in exchange for the ransom. The information about the ransom sum is not being released, Somali officials and a maritime monitoring group said.

Previously, the pirates were able to made millions of dollars in ransoms for the return of the ships captured by them in the territorial waters of the Horn of Africa countries. However, the number of such cases has significantly declined due to the intensified patrolling of the Indian Ocean by the naval forces of different countries.

Sailors were released on October 30.They were held hostage since September 2010, when the pirates hijacked the Panamanian ship MT Asphalt Venture. The rest of eight crew members along with the ship were freed in exchange for the ransom in April 2011.

Then the pirates claimed that they would release the remaining seven hostages only provided that Indian officials would free the pirates held by them.

It remains unknown whether their demand was fulfilled or not.

Ecoterra International organization, based in Kenya, which monitors maritime activity in the Indian Ocean, confirmed that the mariners were released by the pirates.

“The remaining seven hostages ...  were finally freed by their captors against a ransom and arrived in Mogadishu, the capital of Somalia, from where they will be flown directly to India,”  Ecoterra International  said in a statement.

According to officials, the regional government assisted in mariners’ release in Haradhere in Central Somalia.

The last high-profile case of the ship attack outside the territory of Somalia was earlier this year, when the pirates managed to seize a merchant ship in the Red Sea.

In 2011, when Somali pirates were more active, they were able to hold more than dozens of merchant ships at a time, often demanding multimillion-dollar ransoms.