At least two people were injured in another explosion here Sunday night, after three package bombs detonated earlier this month in other parts of the city and killed two people and injured two others.

Officials said the explosion in southwest Austin injured two men in their 20s who were hospitalized. There was no immediate word on what caused the blast. Police blocked off the entrance to the suburban neighborhood where it occurred and urged people living nearby to stay in their homes.

The latest explosion came hours after authorities raised the reward for information leading to the arrest of whoever is responsible for the first three explosions to $115,000.