U.S., Australian and Russian authorities teamed up to arrest 10 people accused of kidnapping a couple near Moscow and trying to extort $1.6 million from their relatives in New Jersey, the FBI said Friday.

The Australian couple were held eight days before the FBI, working with a former branch of the Soviet KGB and Australian federal police, discovered where they were being held, the FBI said in a statement. On Wednesday, Russian police raided a dacha about 50 kilometres outside Moscow, freeing the woman and arresting five people, the FBI said.

Thursday, Russian authorities stormed a Moscow hotel room and released the businessman, arresting another five people. Authorities found them by monitoring phone calls to relatives, the FBI said.

Although authorities wouldn't identify the couple, a Philadelphia lawyer involved in the case said they are Daniel and Ivonny Weinstock.

Dimitry Afanasiev, of a Philadelphia law firm, said the businessman's company, SovAustralTechnika, is an Australian-Russian electronics firm. Afanasiev, whose firm has extensive Russian connections, said he established links between the FBI and the Russian Agency for Federal Security, formerly a branch of the Soviet KGB...