The Indian navy arrested 23 pirates who threatened a merchant vessel Saturday in the lawless waters of the Gulf of Aden, where dozens of ships have come under attack by gunmen in recent months. An Indian navy ship, the INS Mysore, was escorting merchant ships in the region when it received a distress call from seamen on board the MV Gibe, who said they were being attacked by two boats. The distress call said the boats were firing on the Gibe, according to a statement from the Indian government. The pirate boats attempted to escape when they saw the Mysore and its helicopter, but were boarded by Indian marine commandoes, the statement said. The pirates had "a substantial cache of arms and equipment," including seven AK-47 assault rifles, three machine guns, a rocket-propelled grenade launcher and other weapons, the statement said. They also found a GPS receiver and other equipment.