Former prime minister Manmohan Singh tested positive for Covid-19 and was admitted to AIIMS with a mild fever on Monday afternoon.
Dr. Singh, 88, has been admitted to the AIIMS trauma centre here, which is a dedicated COVID facility, sources said, adding his condition is stable.
They said Dr. Singh had a mild fever in the morning and later tested positive for Covid-19.
The doctors are monitoring his condition.
Dr Singh has received his two vaccine doses (of Covaxin) - the first on March 4 and the second on April 3. Sources said he was shifted to hospital as "a matter of precaution".
On Saturday, Dr Singh participated in a meeting with top Congress leaders, including Sonia Gandhi, Rahul Gandhi and Priyanka Gandhi Vadra, on the Covid situation in the country.
Following this, he wrote to prime minister Narendra Modi on Sunday, to offer some advice on handling a pandemic that has infected over 1.5 crore Indians and killed nearly 1.8 lakh.
He urged Modi to allow states to define categories of frontline workers that need to be vaccinated against Covid on priority "even if they are below 45 years of age" - something experts and the chief ministers of several Congress-ruled states have also flagged.
(With inputs from NDTV.com)