Maritime officials said pirates off the coast of Somalia Friday hijacked another ship and released one that had been held for more than two months.

Officials said three crew members escaped as pirates boarded the Liberian-flagged chemical tanker Biscaglia.

A warship on patrol near the ship sent a helicopter to intervene.  It arrived after pirates seized the ship, but rescued the three crew members who had jumped into the Gulf of Aden.

At least 25 other crew members are still on board the hijacked ship. They are reported to be mostly from India and Bangladesh.

Also Friday, Kenyan authorities said Somali pirates released a Greek ship they captured in September. The ship's 26 Filipino crewmembers are reported to be in good health after two months in captivity.

Somalia pirates are holding about 15 ships, including a Saudi tanker carrying $100 million worth of oil.  Pirates are demanding $15 million for the tanker.

An international coalition of warships patrols the area off Somalia to prevent hijackings.  

Pirates based in Somalia have made the waters off East Africa some of the most dangerous in the world. 

Some information for this report was provided by AFP, AP and Reuters.