 The first bus in a convoy hit a remote controlled mine, and the militants then opened fire on the line of vehicles from the ruins of a nearby high-rise building.Another version of the attack was presented by "Nezavisimaya Gazeta", which claimed there were two connected attacks.The incident preceded by two hours President Vladimir Putin's mid-term state-of-the-nation address, in which he said the "military phase" of the Chechen conflict had been completed.