A South Korean container vessel which escaped an apparent hijack by pirates off Somalia on Thursday is back to normal sailing, owners Hanjin Shipping Co. said Friday.

“The Hanjin Tianjin began to sail Thursday night, escorted by the South Korean destroyer Choi Young, right after its crew had been rescued,” a Hanjin Shipping official said. “It is speeding up to reach its next port in Singapore because its sailing was delayed by the pirates’ attack.”

The container ship, which has 20 crew members aboard, lost contact with Hanjin Shipping early Thursday while in waters off Somalia. Seoul officials presumed it had been hijacked by pirates known to frequent the area. Naval commandos of a South Korean unit operating off the Somali coast were dispatched to the ship, where they found no pirates. They rescued the crew who had hidden inside the citadel, a bulletproof safety zone in the ship.

“All crew members are in good health. If they think they need or ask for a medical checkup, we will take steps after the ship enters the port,” he said.

The official added that the crew found no problems with the engine, steering gear and cargo except slight damage to the hull due to apparent rifle attacks by pirates.

The Hanjin Tianjin is scheduled to go to Shanghai and China via Singapore. Then it will head for Europe, without entering the port in Busan, Korea.

The company is considering installing a satellite communication device inside the citadel soon after the ship arrives in port, the official said.

The military estimates that there were 16 pirates. A senior officer of the Joint Chiefs of Staff told the related National Assembly committee Friday that a helicopter and the Choi Young destroyer had fired warning shots as they reconnoitered near the ship before rescuing the crew successfully.

On Thursday night, all 20 crew members were confirmed safe.

Naval commandos of the Cheonghae Unit, a South Korean anti-piracy contingent operating off the Somali coast, boarded the 75,000-ton ship. They searched the ship, but found no pirates and rescued 14 South Koreans and six Indonesians, who had been locked inside the citadel, at around 7:30 p.m.

The Panamanian-registered ship lost contact at around 5:15 a.m.

“We will do our utmost to enhance maritime security and international peace in the region under the principle that our

military will never make any compromise with pirates,” the Joint Chiefs of Staff spokesperson Col. Lee Bung-woo said Thursday night.

The attack came about three months after South Korean 11,500-ton chemical freighter Samho Jewelry and its 21 crew were rescued by the Navy days after it being seized in the Arabian Sea between Oman and India.

The Cheonghae unit was deployed in March 2009 to join an international anti-piracy campaign in the Gulf of Aden off the Somali coast.

Somalia has been in a state of civil war for two decades and has not had a functioning central administration since Mohammed Siad Barre was ousted in 1991. The African country has a coastline facing one of the busiest shipping routes in the world.

A U.S.-led military intervention to restore order in Somalia began in December 1992. However, the efforts failed and international forces pulled out in 1995 due to the growing danger to troops.

By Song Sang-ho (sshluck@heraldcorp.com)