About 20 Filipino seamen kidnapped by pirates in Somalia in March have been released and are on their way home, officials said Monday.

The men were freed Saturday, and it was not clear whether any ransom has been paid, said Roy Cimatu, the government's special envoy to the Middle East.

The men were seized after their oil tanker, the United Arab Emirates-registered MT LIN1, offloaded its cargo at a southern Somali port on March 29, the Philippine Foreign Affairs Department said.

Cimatu said the owners of the ship, who were not identified, negotiated for the release of the men. No other details were provided.

Piracy in Somalia rose sharply last year, with the number of reported incidents at 35, compared with two in 2004, according to the International Maritime Bureau. The bandits target both passenger and cargo vessels for ransom or loot.