CNN said it fell from a
Tu-160, much faster than a C-130 (1,380 MPH).
That is also what is being reported by the Russians however as far as I can tell there has been no independent verification of that and I don't want to sound conspiratorial... however I have a difficult time believing that a Blackjack could carry a weapon the
size and weight of a MOAB given strategic bombers are designed for significantly smaller ordinance, even when the total payload weight is greater than that of a MOAB.
I could be wrong though... the Russians very well could have modified a Blackjack to drop such a thing, or even something smaller if they really were that efficient at reducing the size of the weapon... in which case it is still only of limited effectiveness
as the bomber would still be detectable and interdicted.