Respiratory parameters of former president Pranab Mukherjee have shown a slight improvement, though he continues to be on ventilator support, the hospital said on Thursday.

Mukherjee, who was admitted to the Army's Research and Referral Hospital on August 10, developed a lung infection on Wednesday.

Doctors attending on him said his vital parameters remain stable.

"The respiratory parameters of Hon'ble Shri Pranab Mukherjee have shown slight improvement though he continues to be on ventilatory support. His vital and clinical parameters remain stable and are being closely monitored by a team of specialists," a hospital statement said.

Mukherjee was operated on for removal of a clot in the brain on August 10 at the Army Hospital in Delhi Cantonment.

He was also tested positive for Covid-19.

Mukherjee was the 13th President of India from 2012 to 2017.