US Navy frees vessel, 9 Iranian crew members after seizing drugs; incident happens on Monday.

US Navy said Thursday its ships seized 385 kilograms (849 pounds) of heroin worth about $4 million from a stateless fishing vessel in the Arabian Sea.

US Coast Guard personnel aboard USS Tempest (PC 2) and USS Typhoon (PC 5) discovered the illegal shipment, the US Navy's Fifth Fleet in Bahrain said in a statement.

The seizure took place on Monday and the confiscated drugs were destroyed at sea by US forces.

"The U.S. Navy released the stateless fishing vessel and its nine crew members, who identified themselves as Iranian nationals, after seizing the drugs," said the statement.

The ships were operating as part of an international task force called Combined Task Force (CTF) 150 to combat unlawful maritime activities.

"This latest seizure is a demonstration that CTF 150 and assigned surface and air assets are ready to conduct interdiction operations 365 days a year," said Royal New Zealand Navy Capt. Brendon Clark, the commander of CTF 150.