TOKYO (Reuters) — Japanese Prime Minister Shinzo Abe, the nation’s longest-serving head of government, resigned due to his worsening health on Friday.

Abe has battled the disease ulcerative colitis for years and two recent hospital visits within a week fanned questions on whether he could stay in the job until the end of his term as ruling party leader in September 2021.

He said his health started declining around the middle of last month and he did not want it to impact on important policy decisions.

Abe was scheduled to held a news conference early Friday morning in the U.S.

As the news spread, Japan’s benchmark Nikkei average fell 2.12% to 22,717.02, while the broader Topix shed 1.00% to 1,599.70.

Abe’s resignation will trigger a leadership race in the LDP, the winner of which must be formally elected in parliament.

The conservative Abe returned as prime minister for a rare second term in December 2012, pledging to revive growth with his “Abenomics” mix of hyper-easy monetary policy, fiscal spending and reforms. He also pledged to beef up Japan’s defenses and aimed to revise the pacifist constitution.

On Monday, Abe surpassed a record for the longest consecutive tenure as premier set by his great-uncle Eisaku Sato half a century ago.

Abe resigned from his first stint as prime minister in 2007, citing ill-health after a year with scandals in his cabinet and an election loss for his ruling party. He had since kept his illness in check with medicine that was not previously available.

This is a developing story.