The Chechen conflict entered a new phase on 1 October 1999, when Russia's new Prime Minister Vladimir Putin declared the authority of Chechen President Aslan Maskhadov and his parliament illegitimate. At this time, Putin announced that Russian troops would initiate a land invasion but progress only as far as the Terek River, which cuts the northern third of Chechnya off from the rest of the republic. Putin's stated intention was to take control of Chechnya's northern plain and establish a "cordon sanitaire" against further Chechen aggression; he later recalled that the cordon alone was "pointless and technically impossible," apparently because of Chechnya's rugged terrain. According to Russian accounts, Putin accelerated a plan for a major crackdown against Chechnya that had been drawn up months earlier.