Washington: The US ambassador to India resigned on Monday in the wake of a bitter rift between the usually friendly countries following a diplomat`s arrest in New York.
The announcement by veteran envoy Nancy Powell comes days before India heads into elections in which Hindu nationalist Narendra Modi -- formerly a US pariah -- is forecast to become prime minister.
Powell, in a brief statement, did not elaborate on her reasons but said that her decision was "planned for some time" and that she will retire by the end of May in the eastern US state of Delaware.
She has been ambassador for less than two years.
She is leaving after the worst crisis between the United States and India since the nations started building a warmer relationship following the Cold War.
India voiced outrage in December when one of its diplomats, Devyani Khobragade, was arrested and strip-searched in New York on charges of underpaying her servant.
US diplomats came under criticism for not responding more quickly and forcefully to calm the furor after Khobragade`s arrest, which led to Indian countermeasures against US diplomats.
Khobragade returned to India under a deal, but prosecutors went ahead in March with a second indictment.
A US congressional aide said Powell has found it difficult to arrange meetings with Indian officials since Khobragade`s arrest.
"She was there at a fairly tough time, when political churn on both sides made it difficult to do anything big in the relationship. So, with elections coming up, it`s a natural time for the US to start anew with a new government," the aide told AFP on condition of anonymity.
Even before Khobragade`s arrest, Indian and US commentators had increasingly charged that the growing relationship between the world`s two largest democracies was failing to live up to its billing.
"I think it`s fair to say that she`s been caught in a negative news cycle about India-US relations and, irrespective of why she resigned, the appointment of a new ambassador at a time of electoral transition in India could have positive benefits," said Milan Vaishnav, an expert at the Carnegie Endowment for International Peace.
State Department spokeswoman Marie Harf insisted that Powell simply wanted to retire and that it was "totally false" to link her decision to recent tensions.
Powell, who holds the prestigious title of career ambassador, had a 37-year career in which she also served as the top US diplomat in Ghana, Nepal, Pakistan and Uganda.
In February, Powell broke a US taboo by meeting with Modi, the chief minister of the western state of Gujarat and candidate for prime minister of the right-leaning Bharatiya Janata Party.
The United States had earlier refused Modi a visa on human rights grounds over anti-Muslim riots in 2002 in which more than 1,000 people were killed.
Critics accused Modi of turning a blind eye or worse to the violence, although investigations cleared him of personal blame.
Despite the controversy in Washington over Modi, most policymakers agreed that the United States needed to reach out to him due to the likelihood he will become prime minister.
President Barack Obama will likely face calls to name a prominent new ambassador to demonstrate India`s importance after high-profile appointments to China and Japan.