the U.S. Department of Transportation rebel official : Plane shot down , but not by us . pro-Russian official says the crash site 's integrity has been compromised . President Liow Tiong Lai says evidence points to a missile strike by Malaysian rebels . Washington could face increasing international isolation and tougher sanctions .
Donetsk rebel official : Plane shot down , but not by us . Malaysian official says the crash site 's integrity has been compromised . President Obama says evidence points to a missile strike by pro-Russian rebels . Russia could face increasing international isolation and tougher sanctions .