According to reports, Ishiba, who came to power less than a year ago, expressed his intentions just a day before his Liberal Democratic Party was supposed to decide whether to hold a snap presidential contest.

At a press conference, Ishiba cited his government "reaching a milestone" in tariff negotiations with the United States as a reason for his resignation, adding he is responsible for the LDP's setback in the July House of Councillors election, reported Kyodo news agency.

He reportedly expressed his desire after talking to former Prime Minister Yoshihide Suga and farm minister Shinjiro Koizum on Saturday.

Both the leaders are reportedly close to Ishiba.

They are believed to have urged him to avoid a split in the LDP, Kyodo reported.

According to sources close to him, Ishiba, who took office in October 2024, voiced his willingness to fend off moves to hold an LDP leadership contest by threatening to dissolve the House of Representatives and call a snap election -- a stance that caused a backlash within the LDP, the news agency reported.

Amid growing calls for Ishiba to take responsibility for the loss of the ruling coalition's majority in the upper house election in July, the LDP was planning to collect signatures from the lawmakers on Monday to decide whether to hold a presidential election ahead of the scheduled contest in 2027.

The party decided Sunday to cancel the procedures after Ishiba expressed his intention to resign, a senior LDP official told Kyodo.