Afghanistan, March 30 -- Several explosions were heard in Baghdad early Monday after rockets struck Victory Base, a former U.S. military facility near the capital, in the latest sign that the regional conflict is spilling deeper into Iraq.

According to local and regional reports, the rockets targeted the Victory Base complex, and at least one projectile reportedly hit an Iraqi transport aircraft. There was no immediate claim of responsibility, and no official casualty toll was announced in the first hours after the attack.

Reports said air defense systems failed to intercept the incoming rockets, raising fresh questions about the vulnerability of strategic facilities around Baghdad International Airport, where several military and securit...