The head of the Imperial Household Agency has warned that last week's birth of the first male heir to the Chrysanthemum Throne in four decades did not resolve the Imperial family's succession crisis, an official of the agency said Wednesday.

The birth of Prince Hisahito was hailed by conservatives as averting a crisis in the Imperial system, which allows only males from the male line to reign but was in desperate need of a successor.

Until his birth, Emperor Akihito's sons Prince Akishino and Crown Prince Naruhito had had three daughters between them but no sons.