Authorities in Moscow were Friday holding an Australian citizen who made threats to blow up an Aeroflot passenger plane while flying to the Russian capital from Tokyo. The 28-year-old Sydney resident was detained Thursday at the city's Sheremetyevo-2 airport after trying to force his way into the aircraft's cockpit during the flight, the Itar-Tass news agency reported. The motives of the unarmed man's actions were unclear, officials said.