Sonia Gandhi, India's most powerful politician and the leader of the ruling Congress party alliance, was in stable condition after falling ill during a debate in Parliament.
Press Trust of India, quoting unidentified sources at the hospital where Gandhi was taken, said she was no longer in the intensive care unit, where she had been taken initially because of chest pain.
Gandhi had been suffering from a fever since Sunday, according to news reports. She appeared fine during a parliamentary speech earlier Monday, but reports said she had to be escorted from Parliament in the evening by colleagues and her son Rahul, another leader of the Congress party.
Gandhi, 66, was born in Italy but rose to power after the killing of her husband, former Prime Minister Rajiv Gandhi.
The Congress party has long kept a careful veil over Gandhi's personal life, despite her immense influence. She was flown to the United States for surgery in 2011, with some Indian news outlets saying she had been treated for cancer. But the party never gave more than cursory information about her illness, calling it a personal matter.
She is widely seen as the true power behind Prime Minister Manmohan Singh, the quiet technocrat who has held India's top job since the party returned to power in 2004. Congress has been badly battered over the past year or so by a series of corruption scandals, bitter internal feuding and an inability to deal with a stumbling economy and deep-rooted problems with poverty, infrastructure and education.
India holds its next national elections in 2014.