As soon as Tzazon received his brother's message, he left Sardinia and landed in Africa, joining up with Gelimer at Bulla. The Vandal king now determined to advance on Carthage. His intentions were not clear; the traditional interpretation is that he hoped to reduce the city by blockading it, but Ian Hughes believes that, lacking the reserves for a protracted war of attrition, he hoped to force Belisarius into a "single, decisive confrontation". Approaching the city, the Vandal army cut the aqueduct supplying it with water, and attempted to prevent provisions from arriving in the city. Gelimer also dispatched agents to the city to undermine the loyalty of the inhabitants and the imperial army. Belisarius, who was alert to the possibility of treachery, set an example by impaling a citizen of Carthage who intended to join the Vandals. The greatest danger of defection came from the Huns, who were disgruntled because they had been ferried to Africa against their will and feared being left there as a garrison. Indeed, Vandal agents had already made contact with them, but Belisarius managed to maintain their allegiance—at least for the moment—by making a solemn promise that after the final victory they would be richly rewarded and allowed to return to their homes. Their loyalty, however, remained suspect, and, like the Moors, the Huns probably waited to see who would emerge as the victor and rally to him.