april because of the ongoing connext. no such bans existed for this part of eastern ukraine. >> anderson cooper reporting will. the white house is calling for an immediate cease-fire in ukraine to insure a safe and complete investigation of the crash site and recover sadly and tragically in this case the recovery of the victim's body is something that has to be considered. so, the big question that we have been asking that the world has been asking, what brought down this plane and one of the prevailing theories is a surface-to-air missile system is responsible. here are some details on the missile system that may have brought down malaysia airlines flight 17. the ukrainian administer adviser claims a buc, surface-to-air missile hit the plane. it's russian made, a self propelled missile fired from a launcher, usually mounted on a vehicle like a truck. this is heavy weaponry we are talking about here. it can target a plane up to