Aso came under new pressure to step down from dissident lawmakers in his Liberal Democratic Party concerned about national elections next month in the wake of the party's stunning defeat in recent Tokyo municipal assembly elections.
Some lawmakers Thursday sought to call a decision-making panel this week where they could seek a party presidential poll to replace Aso, Kyodo reported. They want the Joint Plenary Meeting of party members from both houses of parliament held before Aso dissolves the lower house next week ahead of the Aug. 30 balloting.
Those signing the petition included Finance Minister Kaoru Yosano and Agriculture, Forestry and Fisheries Minister Shigeru Ishiba, the report said.
''Now that the signatures have been collected, it is the LDP's responsibility to hold the meeting if the party boasts democratic procedures," Yosano was quoted as telling reporters.
The dissident party members are concerned Liberal Democrats could lose if it campaigns under Aso's leadership, the report said.
Chief Cabinet Secretary Takeo Kawamura said Aso was "ready to respond'' as soon as the leadership decides how to deal with the petition.