Former Defense Minister Shigeru Ishiba, Prime Minister Shinzo Abe's main political foe, said Friday that the ruling Liberal Democratic Party should not rush moves to revise the Constitution's war-renouncing Article 9.

Ishiba made the remark during a news conference in Tokyo. On Sunday, Abe said the LDP should submit constitutional revision proposals to the extraordinary Diet session starting in the fall, presumably including his own proposal to revise Article 9.

Ishiba is set to challenge Abe in September's LDP presidential election, which will also determine the next prime minister.