President Pranab Mukherjee undergoes angioplasty at Army hospital in Delhi

President Pranab Mukherjee on Saturday underwent a heart procedure as doctors at the Army's Research and Referral hospital installed a coronary stent in his artery to remove a blockage.

Mukherjee, 79, was taken to the hospital in the morning after he complained of stomach problems and related ailments. Doctors at the hospital put him under observation for a day for various tests during which they detected a blockage in one of the arteries, hospital sources said.

The doctors immediately conducted angioplasty and installed a stent, a small mesh tube that's used to treat narrow or weak arteries. Coronary angioplasty is a procedure used to open blocked or narrowed coronary (heart) arteries. The procedure improves blood flow to the heart muscle.

When contacted, Press Secretary Venu Rajamony neither confirmed nor denied the reports and said "the President is under care at the hospital and we expect him to be back by Monday."