TOKYO - Japanese Prime Minister Naoto Kan faced a party leadership challenge from a scandal-tainted powerbroker on Thursday, raising the possibility of the country getting its sixth premier in four years.

Ichiro Ozawa, 68, said he would run for the presidency of the ruling center-left Democratic Party of Japan (DPJ) next month in a move that spells more instability for the not yet year-old government.

Ozawa - a major faction leader and veteran of backroom politics dubbed the "Shadow Shogun" - announced his bid to oust Kan in brief comments to reporters, adding that he had the support of ex-premier Yukio Hatoyama.