Let me know of any groups I missed, but as far as I can tell only the Carter Center and the opposition were on the ground and unhappy with the outcome.
The Carter Center seek disaggregated results by polling station to corroborate the results. The opposition took their own exit polls and claim 70% of the vote. All statements by nations are informed by one or both of these groups. That’s why I said the Americans and losers are the ones claiming fraud. The opposition are clearly biased, while the Carter Center I would go on a limb and call USA aligned.