The Soviet Union and its Warsaw Pact allies used their massive superiority in numbers and the idea of Deep Battle to intimidate NATO over the Inner German border. Some Western observers predicted that the Warsaw Pact could use a mixture of speed and surprise to overrun Western Europe in around 48 hours. While massive air strikes using enormous numbers of aircraft would devastate NATO infrastructure and reinforcements, VDV (airborne units), Spetsnaz ("special purpose troops", i.e. special forces) and naval infantry would clear the way for the torrent of tank and motor-rifle divisions that would soon cross the border. The forward units of these tank and motor rifle divisions would be given the task, rather unusually, of avoiding engagements with the enemy and simply to advancing as far and as fast as possible, therefore enabling a victory before any replacement aircraft and REFORGER units came to Europe from North America.