The reported offer was not disclosed but a pirate confirmed the Comoros-flagged Aris 13 was released without a ransom being paid.
Security official Ahmed Mohamed told the AP news agency that pirates agreed to leave after negotiating with local elders and state officials.
The hijacked product tanker Aris 13 was released by pirates without condition and ransom after gunshots with local naval forces.
PMPF director general Abdirahman Mohamud Hassan was quoted by BBC as saying: "There has been discussion going on after the gunfight this afternoon; we took our forces back and thus the pirates went away".
This would be the first commercial pirate attack off Somalia since 2012, Steed said.
Data on incidents reported to IMO shows that the hijacking of the Aris 13 is the first reported hijacking of a vessel covered by IMO regulations by Somali pirates since the tanker Smyrni in May 2012.More news: National Football League player accepts prom invitation from Wisconsin girl
Yesterday, EU navy forces said the pirates have demanded undisclosed ransom from the owners of the vessel to release it from custody. Authorities disengaged but threatened to use force if negotiations for the crew's release failed. The ship was carrying fuel to Mogadishu when it was approached by two small boats off the coast of Somalia.
He said the vessel was not following the "best practices" put in place to avoid piracy, since it was taking a cost- and time-saving route too close to Somalia's coastline, was travelling too slowly and was without an armed escort. "The ship changed course quite soon after that report and is now anchored".
The area where the pirates operate is also home to one of the eight biggest maritime oil routs, the Bab el-Mandeb channel, through which 3.8 million barrels of crude pass daily. They don't normally kill hostages unless they come under attack, including during rescue attempts.
Steed says there is nothing unusual about the move.
At their height in 2010, bands of Somali pirates hijacked almost 50 ships and captured more than 1,000 sailors, causing an estimated $7 billion loss to the shipping industry. However, they are often harassed by illegal fisherman and large foreign trawlers off the country's north coast.
Though anti-piracy measures ended attacks on commercial vessels, fishing boats continued to face assaults.