The patriots ordered forty of the most decided partisans of Massinissa to be banished from the city, and made the people swear that they would on no account ever permit their return; at the same time, in order to repel the attacks that might be expected from Massinissa, they formed out of the free Numidians a numerous army under Arcobarzanes, the grandson of Syphax (about 600).

Massinissa, however, was prudent enough not to take arms now, but to submit himself unconditionally to the decision of the Romans respecting the disputed territory on the Bagradas; and thus the Romans could assert with some plausibility that the Carthaginian preparations must have been directed against them, and could insist on the immediate dismissal of the army and destruction of the naval stores.
The Carthaginian senate was disposed to consent, but the multitude prevented the execution of the decree, and the Roman envoys, who had brought this order to Carthage, were in peril of their lives.
Massinissa sent his son Gulussa to Rome to report the continuance of the Carthaginian warlike preparations by land and sea, and to hasten the declaration of war.

After a further embassy of ten men had confirmed the statement that Carthage was in reality arming (602), the senate rejected the demand of Cato for an absolute declaration of war, but resolved in a secret sitting that war should be declared if the Carthaginians would not consent to dismiss their army and to burn their materials for a fleet.

Meanwhile the conflict had already begun in Africa.

Massinissa had sent back the men whom the Carthaginians had banished, under the escort of his son Gulussa, to the city.