Ex-Indian President Pranab Mukherjee, who was admitted to the Army Hospital in New Delhi where he tested positive for COVID-19, is "critical and on ventilator support".
A medical bulletin issued by the Army Research and Referral Hospital said he had undergone an emergency lifesaving surgery to remove a large brain clot.
Mukherjee's son Abhijit Mukherjee tweeted seeking prayers for the speedy recovery of his father.
"Please pray for my father #PranabMukherjee for his speedy recovery! We need your good wishes", reads the tweet.
Eighty-four-year-old Mukherjee was the 13th President of India from 2012 to 2017. He served in different positions in the federal government – as foreign, defence, commerce ,and finance minister.
Mukherjee's political career started as deputy minister in the federal Ministry of Industry, Shipping and Transport and junior minister in the Finance Ministry between 1973-74 in a government headed by the late Indira Gandhi. He was also the deputy chairman of the federal Planning Commission from 1991-96.