NEW DELHI: Sonia Gandhi, the leader of India's opposition Congress party, cut short a visit to a northern hilltown and was admitted to a hospital in New Delhi on Friday.

The 70-year-old Gandhi is suffering from a stomach upset and has been admitted for observation, the chairman of the Ganga Ram Hospital, D.S.Rana, said in a statement. The Press Trust of India news agency said Gandhi was brought to New Delhi in an air-ambulance from Shimla, where she had been vacationing.

Gandhi has faced past health problems, but her party has long kept a veil over her personal health. She flew to the United States for surgery in 2011, but the party never provided more than cursory information about her condition.

She has been visiting the United States for regular checkups since then.

In March 2016, she cut short a political rally in northern India due to a high fever and was hospitalized in New Delhi for several days.

Gandhi is the Italian-born widow of slain former Indian Prime Minister Rajiv Gandhi. After his death, she entered politics reluctantly, but led the party to successive election triumphs in 2004 and 2009. Her party lost power to current Prime Minister Narendra Modi's Hindu nationalist party in 2014.—AP