The Indian government said on Thursday it had decided to form a panel to study a controversial nuclear deal with the United States, taking into account objections from communist parties who shore up the coalition.

The announcement came after talks between senior government leaders and their communist allies, who have opposed the deal and demanded it be put on hold, sparking a crisis which has threatened to unseat Prime Minister Manmohan Singh's coalition.

A day earlier, the communists had demanded a government assurance that it would not pursue negotiations seeking global approvals for the deal before the left parties joined the panel.

But Thursday's statement gave no such assurance, which a senior member of the government privately said was not possible.

Foreign Minister Pranab Mukherjee said the government had decided to form a panel in view of certain objections raised by the left parties to the agreement, seen as a cornerstone of a growing friendship between India and the United States.

The panel would look into certain aspects of a bilateral nuclear agreement finalized last month and what implications a framework American law would have on India's nuclear self-reliance -- issues raised by critics of the deal.

It would also study the implications of the nuclear agreement on foreign policy and security cooperation, the minister said. Members of the panel would be announced soon.

The operationalisation of the deal will take into account the committee's findings, he told reporters.

The civilian nuclear cooperation deal aims to lift a three-decade ban on sales of U.S. nuclear fuel and reactors to India, imposed after it conducted a nuclear test in 1974 while staying out of non-proliferation agreements.

While the deal has been hailed as historic by Washington and New Delhi -- who were on opposite sides of the Cold War -- the communists say it compromises India's sovereignty and imposes American hegemony.

Analysts say the panel would give the government time to convince the communists while pursuing key global approvals needed before nuclear trade between the two countries can begin.

India needs to conclude a safeguards agreement with the International Atomic Energy Agency, get unanimous backing of the Nuclear Suppliers Group and the approval of the U.S. Congress before the deal can come into force.