DEVELOPING STORY: Four Americans aboard a yacht hijacked by Somali pirates have been killed, Fox News has confirmed.
U.S. forces responded to gunfire aboard the yacht Quest at approximately 1 a.m. Tuesday, but discovered all four hostages had been shot by their captors. Despite attempts to save their lives, all four hostages died of their wounds.
“We express our deepest condolences for the innocent lives callously lost aboard the Quest,” said Gen. James N. Mattis, U.S. Central Command Commander in a news release.
Two pirates died during the confrontation and 13 were captured and detained, along with two pirates already in custody. U.S. forces also found the remains of two other pirates already dead aboard the vessel and believe a total of 19 pirates were involved in the hijacking.
The yacht Quest was hijacked on Friday off the coast of Oman and U.S. forces had been closely monitoring the vessel.
The Quest is owned by Scott and Jean Adam, a couple from California. The Blue Water organizers also identified the other two Americans onboard as Phyllis Mackay and Bob Riggle.
"We feel desperately sorry for our four friends onboard and our thoughts are with them and their friends and family. All the yachts still on the rally are fine and well," the Blue Water website said.
The Adams have been sailing the world with a yacht full of Bibles since 2004. The hijacking of their yacht came two days after a Somali pirate was sentenced to 33 years in prison by a New York court for the 2009 hijacking of the Maersk Alabama. That case ended when Navy sharpshooters killed two pirates holding the ship's captain.
Pirates have increased attacks off the coast of East Africa in recent years despite an international flotilla of warships dedicated to protecting vessels and stopping the pirate assaults. Multimillion-dollar ransoms are fueling the trade, and the prices for releasing a ship and hostages have risen sharply.
Pirates currently hold 30 ships and more than 660 hostages, not counting the attack against the Quest.
The best-known case of Westerners being held hostage in Somalia was that of Paul and Rachel Chandler, a British couple held for 388 days. The two, who were captured while sailing in their private yacht, were released in November.
The Adams -- who are members of the Marina del Rey Yacht Club in Marina del Rey, Calif. -- run a Bible ministry, according to their website, and have been distributing Bibles to schools and churches in remote villages in areas including the Fiji Islands, Alaska, New Zealand, Central America and French Polynesia.
This is a developing story. Please refresh for additional updates.
The Associated Press contributed to this report.