They augmented their forces by calling in aids from the neighbouring places.

At last Hannibal himself came; nor would the Romans have held out, had not the general body of the Locrians, exasperated by the pride and rapacity of the Carthaginians, leaned towards the Romans.
7.

When Scipio received intelligence that the posture of affairs at Locri had become more critical, and that Hannibal himself was approaching, lest even the garrison might be exposed to danger; for it was not an easy matter for it to retire thence; as soon as the direction of the tide in the strait had changed, he let the ships drive with the tide from Messana, having left his brother, Lucius Scipio, in command there.

Hannibal also sent a messenger in advance from the river Butrotus, which is not far from the town of Locri, to desire his party to attack the Romans and Locrians at break of day in the most vigorous manner, while he on the opposite side assaulted the town, which would be unprepared for such a measure, as every one would have his attention occupied with the tumult created in the other quarter.

But when, as soon as it was light, he found that the battle had commenced, he was unwilling to shut himself up in the citadel, where, by his numbers, he would crowd that confined place; nor had he brought with him scaling-ladders to enable him to mount the walls.
Having, however, had the baggage thrown together in a heap, and displayed his line at a distance from the walls to intimidate the enemy, while the scaling-ladders and other requisites for an assault were preparing, he rode round the city with some Numidian horsemen, in order to observe in what quarter the attack might be best made.