I have heard of two candidates claiming victory in a presidential contest, but three? That’s unusual. But that is precisely what is happening in Gabon, where voters went to the polls to choose a new president.
One might think that this means that the president is elected by plurality, and the race among the three was thought to be close. But, assuming the version of the constitution I located is current,* it takes an absolute majority to be elected (Art. 9). I suppose there could be a close race for second place, with the leading candidate short of majority, and thus all three claiming they are advancing to the runoff. But I am guessing that’s not exactly what any of the three of them has in mind.
In any case, the country is tense as official results, delayed till Wednesday, are awaited.
* But apparently it is not. See Robert Elgie’s comment: the Gabonese constitution now has the president elected by plurality.