Japan's Shinzo Abe returns to hospital on day he becomes country's longest-serving Prime Minister

Japan's Prime Minister Shinzo Abe wearing a face mask arrives at Keio University Hospital for a clinical examination in Tokyo on Monday.

Tokyo (CNN)Japanese Prime Minister Shinzo Abe returned to the hospital on Monday on the day he became the country's longest serving head of government in terms of consecutive days in office.

Abe, leader of the world's third-largest economy, has now served 2,799 consecutive days as Prime Minister -- surpassing the previous record set by his great-uncle, Prime Minister Eisaku Sato, who stepped down in 1972.
The Prime Minister gave brief comments to reporters after leaving the hospital Monday. He did not say what was ailing him, but expressed support to "those who have supported me even during very difficult times."
    "Today I learned more about last week's test, and I've taken an additional test. While seeing to my health, I would like to do my best in my work. I will address the matter about the additional test (in the future)," he said, without specifying what test he actually took.
    Abe suffers from colitis, a non-curable inflammatory bowel disease, which forced him to resign during his first stint as the country's leader from 2006 to 2007. He became Prime Minister again in 2012, finally closing a revolving door of Japanese leaders.
    Chief Cabinet Secretary Yoshihide Suga said the visit Monday was a follow-up to a checkup last week and has not seen "any notable change" from Abe.
    It's unclear exactly how serious Abe's health concerns are, but many in his inner circle said that medication was keeping his condition in check. As leader, he's been credited with revive the country's stagnant economy, though major issues like massive government debt and an aging population loom large.
    But last week marked the first time Abe's health had become a talking point in Japanese politics in years. He is already facing criticism for his handling of the country's coronavirus outbreak, and has seen support among voters drop, adding to speculation that he could resign after reaching Monday's milestone.
    Abe spent spent more than six hours last week at a hospital in Tokyo for what a source with close ties to the Prime Minister described as "ongoing intestine sickness." The individual spoke on the condition of anonymity because that person was not authorized to speak officially about Abe's health. CNN has reached out to the Prime Minister's office for comment.

    Japan's coronavirus crisis

    While there have been no outright comments from the government that Abe's latest health issues could force him to step down, his handling of the pandemic and the ensuing economic crisis has provided his political opponents with an opening.
    Cases of Covid-19 have been rising throughout Japan since mid-July. While government officials and doctors say the higher caseload is the result of more testing, they also say the rise in the number of critically ill is worrying in one of the fastest graying societies in the world.
    Fatigue over social distancing measures is fueling defiance among some, and the streets of Tokyo have started to fill during the day. More than half of the 63,219 cases that have been identified in the country since the pandemic began have been recorded since July 1, but the government has said it has no plans to declare a state of emergency, as it did during Japan's first outbreak.
    The virus has also severely dented economic activity and upended much of the Prime Minister's so-called "Abenomics" agenda that sought to pull the country out of years of deflation. Japan reported its worst drop in GDP on record last week, shrinking 7.8% in the second quarter compared with the previous quarter. That translated to an annual rate of decline of 27.8%, the worst since modern records started in 1980.
      Public opinion of Abe's handling of the coronavirus outbreak and the associated economic downturn has also faltered. A poll by the Mainichi, one of Japan's biggest newspapers, found that 58.4% of people were not content with Abe's handling of the pandemic. His approval rating dipped to 36%, the lowest it has been since Abe took office for a second time in 2012.
      Abe's rivals and opposition parties have been jockeying for position in readiness for the prospect of the Prime Minister stepping down because of his handling of the virus and the deepening recession. Political analysts say Abe's health has added another layer of uncertainty and urgency about his future.