I don’t know. But he is the who one declared it across the whole country and has kept it in place through his own election.
Also he said the country would hold elections if the US provided security funding and paid for other aspects of holding the election, so either that was yet another shakedown of the US or he thought it would have been okay to lift Martial Law in time for the elections, or there is a provision somewhere to allow for elections during Martial Law.