A South Korean destroyer rescued a Panama-registered oil tanker from pirates in Somali waters on Wednesday.

The Joint Chiefs of Staff said Thursday that the 45-hundred-ton “King Munmu the Great” destroyer of South Korea’s Cheonghae Unit received a distress call from the Panama-registered Nepheli around four-fifty p.m., Korean time, on Wednesday near waters off the Yemeni port city of Mukallah.

The South Korean destroyer immediately deployed a helicopter, which successfully deterred four big ships and a dozen small boats carrying pirates.

The Joint Chiefs of Staff said the Nepheli sent a message of appreciation to the Cheonghae Unit after the incident.

Wednesday marked the third time the King Munmu has engaged in anti-piracy activities. The destroyer repelled a pirate attack on a North Korean ship earlier this month and another one aimed at a Denmark-registered ship in April.