US Ambassador to India Nancy Powell is seen upon arrival of US Secretary of State John Kerry (not shown) in New Delhi in this June 23, 2013 file photograph. [Photo/Agencies]

NEW DELHI -- The US Ambassador to India, Nancy Powell, resigned late Monday evening, barely a week before the country goes to polls.

In a statement posted on the US Embassy website, Powell said she had submitted her resignation to US President Barack Obama and would "retire to her home in Delaware before the end of May."

Powell's resignation has triggered media speculation that the move was to placate India's controversial politician Narendra Modi, who is widely tipped to be the next prime minister of this country if the main opposition Bharatiya Janata Party comes to power.

Powell, who apparently shares an uneasy relationship with Modi, may be replaced by the head of the USAID, Rajiv Shah, an American of Indian origin, who is also a Gujarati, according to the media.

Modi, a three-time Chief Minister of the western Indian state of Gujarat, has been barred from visiting the US for his alleged role in the 2002 communal riots in the state, in which over 1,000 people, mostly minority Muslims, were killed.

He denies any wrongdoing and is not yet convicted by a court of law in India.