Indian PM Manmohan Singh has told US President George W Bush he is having difficulty implementing a controversial nuclear deal with the United States.
Mr Singh has described the deal with the US as "historic"
Mr Singh had briefed Mr Bush by phone on Monday, a government statement said.
Differences between the Congress-led government and its allies over the deal has led to talk of early elections.
It is the first clear sign India may shelve the deal, which could end its international isolation on the nuclear issue and provide a key energy source.
The BBC's Sanjoy Majumder in Delhi says it appears the Indian government does not want to face a snap election.
The Congress party's communist allies say the deal, which would allow India access to civilian nuclear technology and fuel, gives the US leverage on India's foreign policy.
After many weeks during which the government insisted it would press ahead with the deal, it now appears to have backtracked in the face of opposition, our correspondent says.
India would be able to use US technology in its nuclear facilities
Mr Singh, on an official visit to Africa, called Mr Bush and discussed the nuclear deal, among other things, according to a government release.
"The prime minister explained to President Bush that certain difficulties have arisen with respect to the operationalisation of the India-US civil nuclear co-operation agreement," the release said.
Mr Singh said last week that the nuclear agreement was "an honourable deal that is good for India and good for the world".
He said, however, that if the deal did not come through, he would be disappointed - but he could live with it.
"One has to live with certain disappointments. We are not a one-issue government. The deal not coming through is not the end of life," he added.
"The government is trying to reconcile the divergent points of view on the issue within the ruling coalition."
The deal has also been criticised by many outside India.
Under the landmark nuclear deal, India is allowed to reprocess spent nuclear fuel - something that is seen as a major concession and opposed by some members of the US Congress as India has not signed the nuclear Non-Proliferation Treaty.
US state department spokesman Tom Casey said his government wanted the deal done as quickly as possible, "but that's within the context of what each country has to do and has to accomplish".
But he added: "I'm not going to try and tell the Indians how to manage their own internal processes."