The condition of former prime minister Atal Bihari Vajpayee has worsened over the past 24 hours and he has been put on life-support system, the AIIMS said in a statement on Wednesday night.
The 93-year-old Bharatiya Janata Party leader was admitted to the premier All India Institute of Medical Sciences on June 11 with a kidney tract infection, urinary tract infection, low urine output and chest congestion.
"Unfortunately, his condition has worsened over the last 24 hours. His condition is critical and he is on life-support system," the AIIMS said in the statement.
Prime Minister Narendra Modi visited the AIIMS in the evening to enquire about the condition of Vajpayee.
Modi reached the hospital at around 7.15 pm and spent about 50 minutes there.
After Modi, Railway Minister Piyush Goyal and BJP MP Meenakshi Lekhi also paid a visit.
Earlier in the evening, Union Textiles Minister Smriti Irani had visited the hospital to check on Vajpayee.
Vajpayee, a diabetic, has only one functional kidney. He had suffered a stroke in 2009 that weakened his cognitive abilities. Subsequently, he developed dementia.