The agency alleged the woman was involved in preparing a "terrorist attack" by Ukrainian intelligence against a Russian law enforcement facility.
The FSB said electronic countermeasure equipment detected the device while the woman was near the alleged target. Bomb technicians who examined the device, the agency said, concluded it was a homemade explosive with a destructive power equivalent to 1.5 kilograms of TNT and was fitted with shrapnel.
The agency also said it detained a citizen of an unnamed Central Asian countries who allegedly planned to detonate the device remotely. The FSB said the woman told investigators she did not know there was a bomb in her backpack and that she had previously been used as a front person in fraud schemes targeting Russians. The agency claimed the detainee confessed and said the weapons were taken from caches set up by Ukrainian special services.
German authorities did not immediately comment on the FSB
statement. The FSB's claims could not be independently verified.