Former President Pranab Mukherjee on Monday underwent brain surgery to remove a clot.
The operation was conducted at the Army Research & Referral Hospital.
Mukherjee was kept on ventilator support after the procedure, sources said.
Notably, prior to his surgery, Mukherjee had also tested positive for COVID-19.
After a long political career in which he held several top posts including that of finance and defence Minister, Mukherjee became President in 2012 and served till 2017.