Somali pirates on Sunday freed a Thai fishing trawler, hijacked off east Africa in October last year, after the payment of a ransom, the EU's anti-piracy mission said.
The Russian foreign ministry said when the boat was captured that it carried a crew of 23 Russian sailors, two Filipinos and two Ghanaians.
"EU NAVFOR can confirm that early this morning a Thailand flagged fishing vessel (Thai Union 3) was released by pirates from the port of Heradere after the payment of a ransom," the mission said in a statement.
It did not give details of the ransom payout.
Heradere, a fishing village 330 kilometres (205 miles) north of Somalia's capital Mogadishu, is considered a base for pirates who have captured dozens of vessels in one of the world's busiest maritime trade routes.
The Thai Union 3 was hijacked on October 29 about 320 kilometres (200 miles) north of the Seychelles and 1,040 kilometres (650 miles) from the Somali coast, the mission said.
Somali pirates hijacked 68 ships in 2009 and raked in an estimated 60 million dollars (44 million euros) in ransom money.
Pirates also boarded and seized a Norwegian-owned chemical tanker on Friday, the ship's owner said.
The UBT Ocean was captured off Madagascar and appeared to have been turned around to head north towards Somalia, said Norwegian shipowner Broevigtank.
The EU anti-piracy mission confirmed the hijacking and said the 21 crew were all from Myanmar.
On March 1 pirates captured a small Saudi tanker and its crew of 14 in the Gulf of Aden, Kenyan authorities said.
They are also holding an elderly British couple whose yacht was captured in October.
Turkey and France meanwhile announced at the weekend they had together captured 29 suspected pirates in the area.
The EU launched its Atalanta anti-piracy mission in a bid to secure the vital shipping lane, joining forces with US-led and NATO missions, as well as other warships dispatched by other naval powers.
But the unprecedented naval deployment failed to curb piracy as Somalia's marauding ransom hunters moved south and started venturing further out in the less heavily-patrolled Indian Ocean, notably towards the Seychelles.
Ransom drops pose a dilemma for governments and companies which want to recover their ships and crews but acknowledge that payments encourage further piracy.