Updated

MOSCOW -- The suicide bomber who killed 35 people and wounded 180 at Moscow's largest airport was a 20-year-old man from the volatile southern Caucasus region, Russian investigators said Saturday.

Breaking a five-day silence over the probe, federal investigators also said foreigners were deliberately targeted, marking an ominous new tactic in Russia's losing battle with extremism.

Islamist rebels from the Caucacus, a group of mountainous Russian provinces that are beset with an entrenched separatist insurgency, have been widely suspected in the attack at Domodedovo Airport.

Saturday's statement from federal investigators confirmed a suicide blast involving a bomb containing shrapnel. While authorities say they know the identity of the perpetrator, they suggested they still don't know who masterminded the attacks.

"Despite the fact that we know the name of the terrorist, we won't name him today ... since investigative searches are ongoing to identify and detain the organizers and accomplices of the terrorist act," the statement said.

Investigators also confirmed fears that foreigners had for the first time entered the terrorists' crosshairs; the victims included one person each from Britain, Germany, Austria, Ukraine, Tajikistan. Kyrgyzstan and Uzbekistan. There were 16 Russian among the dead and the remaining 12 had not been identified.

"It was no accident that the terrorist act was carried out in the international arrivals hall. According to the investigation, the terrorist act was aim first and foremost at foreign citizens," the statement said.

Chechen rebels have claimed responsibility for a number of deadly attacks over the years, including ones against the Moscow subway and at the same airport.