Carlos Pascual, the State Department's special envoy for international energy issues said he was "not too impressed" with India's efforts to cut its imports of oil from Western sanctions-hit Iran, when asked how likely India was to get a waiver from US financial sanctions, Reuters reported.
US secretary of state Hillary Clinton leaned on India last week to cut its imports of Iranian oil further, and said Washington may not make a decision on whether to exempt New Delhi from financial sanctions for another two months.
Clinton, who was on a three-day visit to India, said the U.S. was encouraged by the steps its ally had taken to reduce its reliance on Iranian oil, but that "even more" was needed.
As Tehran's second-biggest crude customer, India is crucial to US efforts to squeeze Iran's economy until it agrees to curb its nuclear programme, which the U.S. and other Western nations suspect is a cover to build atomic weapons.
The issue has become an irritant in ties between India and the United States.