The ship master had sent a distress call to the piracy reporting center, which relayed the alert to international forces policing Somali waters, Choong said. No details about how the pirates attacked or the condition of the crew were available immediately.
Choong said the ship was being operated out of Singapore.
Still on board were 25 Indian and two Bangladeshi crew members, said diplomats who could not be named due to restrictions on speaking to the media. The British security guards escaped by jumping into the water, said a news release issued by their company, Anti-Piracy Maritime Security Solutions.
The company said it was aware of the incident on the chemical tanker it identified as M/V BISCAGLIA.
"We have been informed by coalition military authorities that three of our unarmed security staff were rescued from the water by a coalition helicopter and are currently on board a coalition warship in the Gulf of Aden," the company statement said.
German Defense Ministry spokesman Thomas Raabe confirmed that a naval helicopter lifted three people out of the water in the Gulf of Aden at about 4 a.m. Friday morning and deposited them on a French ship.
Germany and France have ships in the area as part of a NATO fleet which, along with warships from Denmark, India, Malaysia, Russia and the U.S., have started patrolling the vast maritime corridor. They escort some merchant ships and respond to distress calls.
The ship hijacked Friday was the 97th vessel to be attacked this year off Somalia, where an Islamic insurgency and lack of effective government have contributed to an increase in pirate attacks in the Gulf of Aden.
