Somali pirates say they have received a multi-million dollar ransom and released the Thor Nexus, a Thai-owned bulk carrier they seized on Dec. 25.

The 20,377-dead weight bulk carrier was hijacked 350 miles off Oman with crew of 27 Thais on its way to Pakistan.

"We received a $5 million ransom early in the morning for the release of the ship," a pirate who gave his name as Higle told Reuters by phone from their hideout.

The pirates left the ship and it sailed away under the watch of a navy ship that was waiting nearby, Higle said. Foreign navies have been deployed off the Gulf of Aden since the start of 2009 to help prevent piracy, but it was not immediately clear which navy was monitoring the ship.

Pirates make tens of millions of dollars in ransoms from seizing merchant ships in the busy shipping lanes of the Indian Ocean and the Gulf of Aden.

Andrew Mwangura, editor of Somalia Report, an online journal that tracks piracy of east Africa, confirmed the release.

"It was released yesterday and is headed for Mombasa. It is expected within four of five days," said Mwangura. "The ransom was dropped yesterday from a light aircraft onto the ship."

Somalia has lacked an effective central government for two decades, allowing armed gangs to stalk the strategic waterways off the Horn of Africa nation. (Reuters)