( CNN ) -- A Russian heavy missile cruiser stopped three pirate ships off the coast of Somalia , and detained 10 pirates , according to a statement released Friday by Russian Navy headquarters in Moscow . Russian missile cruiser `` Peter the Great '' moored in Cape Town , South Africa , last month . The cruiser , Peter the Great , halted two small high-speed motor boats and a mid-size , support vessel on Thursday , the Russians said . `` Ten pirates have been detained . All of them are citizens of Somalia , '' the press release obtained by CNN stated . `` Officials from the Northern Fleet 's military prosecutor 's office are currently questioning the detainees aboard the Peter the Great . Their future will be decided in coordination with the Russian Foreign and Justice ministries . '' The Russians said a Russian helicopter Ka-27 , which took off from the cruiser , had located two small boats , which were moving toward an Iranian fishing vessel at high speed last Thursday . When those in the boats spotted the helicopter overhead , the boats began slowing down , then veered off toward their support vessel , which was adrift nearby . The helicopter crew could see pirates in the two motor boats throwing weapons into the sea , and kept chasing the boats until the Russian cruiser arrived in the area . `` The three boats were ( captured and ) delivered to the Peter the Great , and ten Somalian pirates were taken aboard . `` The detainees possessed weapons , including a G-3 rifle , an Ak-47 , two AKMS machine-guns , two grenade-launchers and two anti-infantry grenades , and also had a GPS receiver , a ladder , 500 grams of drugs , a large amount of money , a bag of sugar and a bag of rice . The detained pirates were high on drugs , '' the press release said . Meanwhile , Somali pirates have released a Panamanian-flagged , Japanese-owned vessel that was hijacked in the Gulf of Aden in November , according to a non-governmental group that monitors piracy . The ship , named the MT Chemstar Venus , was released late Thursday , according to Ecoterra International . The 18 Filipino and five South Korean crew members were reportedly unharmed . The International Maritime Board , a group that also monitors piracy , told CNN that the company had not confirmed the release of the ship , but said shipping companies sometimes wait a few days before going public to ensure the safety of the crew . The ship was hijacked on November 15 . It was unclear whether the pirates were paid a ransom to release the ship . This incident comes a week after Somali pirates released a Ukrainian ship carrying tanks , ammunition and crew after receiving a ransom of $ 3.2 million . -- CNN 's David McKenzie contributed to this report .
Russian cruiser halted two small high-speed motor boats and a support vessel . Russia : 10 pirates have been detained -- all of them are citizens of Somalia . MT Chemstar Venus released late Thursday , Ecoterra International says . Follows release of Ukrainian ship carrying tanks after a $ 3.2M ransom was paid .