A U.S. warship of those combating piracy off Somalia has rescued three Yemeni fishermen after pirates took their boats and threw them into the sea.

The fishermen, ages 18-36, were found 36 nautical miles off Shabwa in southern Yemen fighting waves for hours in the Arabian Sea.

The U.S. ship handed over the Yemenis to the Yemeni authorities.

Earlier, the south-based Coastguard said they were alerted about a boat that went missing with four crew members onboard.

The alert said the boat vanished on Sunday off Shabwa, prompting an extensive search by the authorities in cooperation with local fishermen.

Foreign anti-piracy troops in the region have rescued and released many fishermen who were attacked by Somali pirates.

The forces came to the region as pirates stepped up their attacks against merchant vessels off Somalia.