Kunio Hatoyama's resignation Friday as internal affairs and communications minister has fueled speculation he could join his brother Yukio, leader of the main opposition party, in a two-pronged family attack on Prime Minister Taro Aso, the grandson of their grandfather's archrival.

The minister quit his Cabinet post after the recent kerfuffle over the management of Japan Post Holdings Co., a symbol of Japan's postal privatization reforms.

After tendering his resignation to Aso, Kunio, who has been a close ally of the prime minister, told reporters, "I will consult with my fellows" on whether or not he will leave the Liberal Democratic Party. On Saturday in Fukuoka, he said he does not plan to leave the LDP at the moment.