WASHINGTON ( CNN ) -- The U.S. Navy arrested nine more suspected pirates off the coast of Somalia Thursday -- the second capture in two days -- after receiving a distress call from an Indian-flagged commercial ship . Suspected pirates are arrested in the Gulf of Aden . According to the Navy announcement , at 4 a.m. local time the Indian-flagged Premdivya sent a distress call to all ships in the area reporting that she had been fired upon by a small skiff , and suspected pirates were attempting to board it . A U.S. Navy helicopter crew was launched from the USS Vella Gulf and fired two warning shots at the small boat to get them to stop . A Navy boarding team was then launched to investigate the skiff 's crew and found rocket-propelled grenades and other weapons on board the small craft , according to Navy officials . The suspected pirates were taken aboard the USS Vella Gulf and processed . They 'll be moved to a temporary holding facility aboard the larger USNS Lewis and Clark , according to the statement . The Navy is now holding a total of 16 suspected pirates while the U.S. and Kenyan governments work out legal details on how the suspects will be moved to Kenya for prosecution . Last month , the United States and Kenya signed an agreement saying that suspected pirates captured by U.S. ships will be moved to Kenya to be tried for their crimes . The capture Wednesday of seven suspected pirates marks the first time the United States was able to capture and hold pirates since its forces began patrolling the dangerous waters off Somalia . Piracy has become a chronic problem off the Horn of Africa in recent years , with some pirates operating from largely lawless Somalia . Pirates attacked nearly 100 vessels and hijacked as many as 40 in the waters off the coast of Somalia in 2008 , according to the International Maritime Bureau . The task force led by the Vella Gulf was set up in January in an effort to clamp down on the attacks in the region , the southern approach to the Red Sea and the Suez Canal .
Nine suspects arrested off the coast of Somalia . The U.S. Navy has been conducting a search and rescue operation in international waters for more than two weeks to try to find those missing after their boat was hijacked by pirates on October 2. United States , Kenya working out legal details .