Updated

SEOUL, South Korea -- South Korea deployed a warship to track down a container ship believed hijacked Thursday by Somali pirates in the Indian Ocean, and the European Union reported that an Italian-flagged ship with 21 crew had been seized.

The South Korean government, which sent commandos to rescue a ship in January in an operation that left eight pirates dead and five others in custody, said it would decline to negotiate with any hijackers in the latest case.

Cho Byung-jae, a spokesman for South Korea's Ministry of Foreign Affairs and Trade, said Hanjin Shipping Co. Ltd. lost contact with the 75,000-ton Hanjin Tianjin early Thursday and suspected it was kidnapped.

Hanjin spokeswoman Sonya Cho said the ship transmitted a coded distress call reserved for pirate attacks when it was about 250 miles east of Yemen's Socotra island. It had a crew of 14 South Koreans and six Indonesians, she said.

Cho said the Choi Young, a helicopter-carrying warship with a crew of 200, had been deployed to help in a possible rescue attempt.

"It has been our government's consistent position that we do not negotiate with pirates," he said. "This will not change."

In January, South Korean commandos attacked the ship Samho Jewelry after it had been hijacked, killing eight pirates and arresting five others, with no loss of life to crew members. The surviving pirates were brought back to South Korea and are awaiting trial.

The European Union's anti-piracy task force said Somali pirates hijacked the Italian-flagged MV Rosallia D'Amato on Thursday as it sailed about 400 miles southeast of the Omani port of Salalah in the Indian Ocean.

It said the 74,500-ton ship was on its way to Iran from Brazil when it was attacked by a single skiff.

Coalition warships had contacted the vessel but were told to stay away as pirates had already boarded the vessel, it said.

There was no further information on the status of the ship's six Italian and 15 Filipino crew members.

The task force also said Thursday that it had returned 18 suspected pirates to Somalia after several countries with an interest in the case declined to prosecute them.

The suspects were detained after an attack April 5 on the Singapore-flagged MV Pacific Opal.
The task force did not name the countries, but normally nations that seize pirates have the right to prosecute them or request other states to put them on trial on their behalf.

Many countries are unwilling to shoulder the burden of a court case or face possible reprisals from other pirates.

According to the U.N. Office on Drugs and Crime's anti-piracy initiative, more than 1,000 Somalis have been convicted or are on trial for suspected piracy.