He told a press conference he started feeling fatigued in mid-July and that doctors found earlier in August that his ulcerative colitis had relapsed. The 65-year-old said he is taking additional medication to treat the condition.

Earlier this year, he worked 147 days straight to deal with the spread of the novel coronavirus in Japan. On August 17, he underwent treatment for UC at a hospital in Tokyo. He visited doctors again a week later for follow-up examinations and told reporters afterward that he hopes to return to work refreshed. But before his press conference, he apparently reported at a meeting of his ruling Liberal Democratic Party that the chronic bowel disease has flared up again.

Abe said he decided to step down as there was a possibility that his condition could deteriorate and force him to resign abruptly, just as he did in 2007.