The spokeswoman, however, would not confirm details of a report by German magazine Der Spiegel which said the two — part of a 12-men crew — escaped during a firefight on Wednesday in which two other crew and up to two pirates were killed.

“Currently two members of the crew are missing,” CEO Niels Stolberg of Beluga Shipping said in a later e-mail exchange. “Two other seamen could be rescued yesterday, and they are safe and sound,” he said, adding that no ransom had been demanded.

According to the Spiegel report, the deaths occurred after a Seychelles patrol boat opened fire on the pirates in an attempt to rescue the ship, named Beluga Nomination. Two crew escaped by jumping overboard in a life boat.

The ship was boarded last Saturday about 800 miles off the Seychelles, far from the areas where pirates mainly operate. But experts say the pirates’ reach is growing as they increasingly use hijacked merchant vessels with hostage crews as giant mother ships to attack shipping deeper in the Indian Ocean.

According the website marinetraffic.com, the Beluga Nomination is 9,775 dead weight tons and flies the flag of Antigua and Barbuda.

Somali pirates are making tens of millions of dollars in ransoms from seizing ships, including tankers and dry bulkers, in the Indian Ocean and the Gulf of Aden, despite the efforts of foreign navies to clamp down on such attacks.

A report this month said piracy worldwide was costing the global economy $7-12 billion a year, with Somali sea-bandits in particular driving up the cost of shipping in the Indian Ocean.

Also on Saturday, another German-based operator said one of its tanker ships carrying chemicals had been attacked on Friday in the Indian Ocean but had managed to escape.

Hamburg-based Chemikalien Seetransport said pirates attacked the New York Star with small arms and rocket-propelled grenades from a small craft and tried to board the ship, which escaped and was being escorted by a Dutch frigate.

German shipping companies and the German government are in talks to deploy military or federal police personnel on merchant shipping at key points to protect them against Somali pirates.