NEW DELHI (AFP) - The head of India's ruling party Sonia Gandhi left on Monday for the United States for a medical check-up, according to a report, a week after she was hospitalised in New Delhi.

Mrs Gandhi was accompanied by her daughter Priyanka, the semi-official Press Trust of India news agency reported, quoting official sources. Her spokesman Tom Vadakkan declined to comment on her trip.

Mrs Gandhi, India's most powerful politician, travelled to the US in 2011 for surgery for an undisclosed condition and remained out of the public eye for three months afterwards. A senior Congress party leader told the news agency Sunday that Mrs Gandhi would be travelling to the US for a medical check-up which was due.

Mrs Gandhi, 66, last had a check-up in the US in February and also travelled there in September last year, the Press Trust of India reported. She was admitted to hospital last week after falling ill during a debate in Parliament on key legislation.

Party colleagues said she had been suffering from fever and was exhausted after days of negotiating the successful passage of a landmark food welfare law. Her health and private life are closely guarded by her advisers, and she rarely speaks to the press.

In 2011 a news magazine report claimed she had undergone surgery for cancer, but her illness has never been officially disclosed.