NEW DELHI: The leader of India's main opposition Congress party offered to resign on Monday, domestic media said, after almost two dozen top leaders called for better decision-making in the party, which has ruled for much of the country's independent history.

The call, made in a letter, is a rare challenge to the Nehru-Gandhi dynasty that has dominated Congress since India won independence in 1947 from colonial ruler Britain. But Prime Minster Narendra Modi's Hindu nationalist Bharatiya Janata Party has dealt the party heavy defeats in two general elections.

Italian-born Sonia Gandhi, widow of former prime minister Rajiv Gandhi, asked the party to relieve her of her role as interim president in a speech to a virtual meeting of the Congress Working Committee, Reuters partner ANI reported.

"Sonia Gandhi asks CWC members 'to begin deliberations towards the process of transition to relieve her from the duty of party president,'" ANI said on Twitter, citing unidentified sources. Two party sources said the signatories to the letter expect the Gandhi family to either play a pro-active role or step down, adding that more than 300 regional Congress politicians also supported the letter. However, several key figures, including the chief ministers of Congress-led states, have publicly backed Gandhi to continue.