Charton said that none of the sailors on board the ship were Swiss but was unable to confirm their nationalities.
A dozen crew members on a Swiss cargo ship have been taken hostage after the vessel was attacked by pirates off the coast of Nigeria, according to the company that owns the ship.
The pirates then destroyed the ship's communications equipment before making off with 12 of the 19 crew members.
Massoel Shipping issued a statement saying it was working with authorities and specialists to ensure a rapid release of those detained.More news: Rare two-headed snake discovered in America
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More than 60 crew were reported kidnapped past year in waters off Nigeria, Africa's leading crude producer, although many attacks are not reported.
Nigerian officials say they are now investigating the incident.
A Massoel spokesman reportedly said the crew members' families are being closely informed of the situation.
A number of foreigners have been kidnapped in the last few years in the southern Niger Delta region, source of most of the oil that is the mainstay of the West African state's economy.
A vessel "sailing under a Swiss flag along the Nigerian coast" has been attacked, the Swiss foreign ministry said in a statement.