Sonia Gandhi, the head of India's ruling Congress Party, has made her first public appearance in India since undergoing surgery in the U.S. for an undisclosed illness.

She participated Sunday in a birthday memorial in New Delhi for independence hero Mahatma Gandhi.

Sonia Gandhi returned to India in early September and resumed work about a week later.

Gandhi appointed a four-member group to run the political party in her absence. The group included her son Rahul, who is widely viewed as a likely future prime minister.

Born in Italy, the 64-year-old Gandhi is the leading figure of a family that has ruled India for most of the period since it won independence from Britain.

She is the widow of assassinated former prime minister Rajiv Gandhi. Her mother-in-law, Indira Gandhi, was also assassinated, while serving as prime minister in 1984. Indira Gandhi's father, Jawaharlal Nehru, was India's first prime minister.

The Nehru-Gandhi dynasty has no family ties to independence leader Mahatma Gandhi.