Sonia Gandhi in hospital

New Delhi - The head of India's opposition Congress party Sonia Gandhi was recovering well after being admitted to hospital in New Delhi with breathing difficulties, a hospital official said on Friday.

Gandhi was admitted to Sir Ganga Ram Hospital on Thursday with a respiratory tract infection and breathing difficulty, hospital official Ajay Swaroop said.

"Her condition is stable and she is recovering well," Swaroop added.

The Italian-born Gandhi is the widow of former prime minister Rajiv Gandhi, who was assassinated in 1991.

She reluctantly entered politics after Gandhi's death and has been Congress party president since 1998.

She led the party to election wins in 2004 and 2009. However, the Congress party lost to the Hindu nationalist Bharatiya Janata Party of current Prime Minister Narendra Modi in general elections held in April-May this year.

There have been concerns over Gandhi's health since she went to the United States for surgery in 2011 for an undisclosed illness.

In 2013, Gandhi was rushed to hospital after she fell ill during a debate in parliament.