Japan Prime Minister Shinzo Abe on Friday said he will resign because of his deteriorating health, Japan Times reported. Abe made the announcement at a press conference convened to address speculation about his health.

The Japanese leader said that given the number of Covid-19 infections have decreased in recent days and new measures for winter have been compiled, “now is the best time to step down”. Abe added he has been thinking about his health and his role as prime minister since June, but did not want to cause a sudden vacancy because of his health.

Abe said a new prime minister needs to be in place before Japan faces influenza and Covid-19 this winter. However, he declined to endorse anyone as his successor and said he will entrust the ruling Liberal Democratic Party to elect the new leader.

Abe’s term ends in September 2021. He is expected to continue till a new party leader is elected and formally approved by the Parliament.

Senior lawmaker and close aide of Abe, Tomomi Inada said Abe had announced his plan to step down at an emergency meeting of the ruling Liberal Democratic Party, according to AFP. “I heard his plan,” she added. “It was sudden and unexpected. I am stunned.”

The news sent Tokyo stocks plunging more than 2%, with the benchmark Nikkei 225 index reversing earlier gains.

Speculation over Abe’s health have been doing the rounds ever since he made two hospital visits within a week earlier this month.

Public broadcaster NHK said Abe wanted to step down to avoid causing problems for his government.

However, Japanese government spokesperson Yoshihide Suga had earlier quashed speculation that Abe may be unable to serve his term and claimed the prime minister remained in good health. “In terms of the prime minister’s health, the prime minister himself has said he wishes to work hard and I see him every day and feel that there is no change in his condition,” Suga had told reporters at a press conference.

Abe made his most recent hospital visit on Monday, the same day he became Japan’s longest-serving prime minister, breaking the record set by his uncle, Eisaku Sato, AP reported. Sato served 2,798 days in office from 1964 to 1972.

Abe has suffered from ulcerative colitis for many years. However, his condition is said to have worsened recently, according to BBC. In 2007, Abe had stepped down as the country’s prime minister, because of an inflammatory bowel disease, after serving only one year in office.