Sudan disconnected from the Internet

Hi, The report from renesys states that "We initially stated that Sudan’s outage began at 12:47 UTC because that was when virtually all Sudanese routed networks were withdrawn from the global routing table" http://www.renesys.com/2013/09/internet-blackout-sudan/ If its a deliberate action to remove Sudan from the Internet then what exactly would the ISPs in Sudan have done? Drop their peering sessions with the three International gateways? How were the "Sudanese routed networks withdrawn"? Glen