NEW DELHI (AFP) - North Korea's atomic bomb test may have dealt a serious blow to the passage of a landmark deal between India and the United States on civilian nuclear energy, analysts said Tuesday.

The deal clinched during a visit by U.S. president George W. Bush to India in March is a cornerstone of Indian foreign policy and aims to bring New Delhi into the "loop of global nuclear commerce" after decades of isolation, said C.U. Bhaskar of the Institute for Defense Studies and Analysis.

Under the terms of the deal, India -- which conducted nuclear tests in 1974 and 1998 and has not signed the Nuclear Non-Proliferation Treaty (NPT) -- will be given access to previously forbidden technology for nuclear power plants.

In return, New Delhi agreed to separate its civilian and military plants and put the former under international safeguards.

Washington on its part agreed to amend its 1954 Atomic Energy Act to allow nuclear commerce and trade in technology with non-NPT signatory, India.

The U.S. Congress gave its thumbs-up to the deal in July but a vote has been delayed in the Republican-controlled Senate that will shortly hold polls to elect new members. Bhaskar warned the North Korean nuclear test "will definitely energize the non-proliferation lobby on Capitol Hill."

"Some U.S. legislators have been saying that this one-time exception in India's case could embolden countries like North Korea to go nuclear," he said.

"North Korea's nuclear test at this juncture complicates matters," he said, adding he was now more cautious about the deal going through.

The collapse of the agreement "will have a vital impact on India's efforts to move away from dependency on hydro-carbons which is what is happening around the world," he said.

"India not getting into the civilian nuclear power generation arena now will have a long term impact" on its rapidly growing energy needs required to power New Delhi's ambitious target of 10 percent economic growth a year.

If the U.S. Senate fails to pass the deal in November, "it will be a setback for both (President) Bush and (Indian Prime Minister) Manmohan Singh," the key players in the deal, Bhaskar added.

India's former ambassador to Washington Lalit Mansingh agreed that the going now seemed tougher.

"The non-proliferation lobby can now ask for amendments to the bill, put tougher conditions for its passage," he said.

If lawmakers of the Democratic Party -- which traditionally has been more hawkish on non-proliferation issues -- win a majority in the Senate in the November elections, "they could use the deal as a tool to embarrass President Bush," Mansingh said.

"If the deal survives till Christmas, it is through, otherwise it is dead. It's an anxious time (for India)," Mansingh added.

Arundhati Ghosh, India's former representative to the Conference on Disarmament in Geneva, said she believed the India-U.S. seal had a "50-50 chance of going through" after Pyongyang's nuclear explosion.

"What is also worrying is that the NSG (Nuclear Suppliers Group that controls the global commerce in nuclear trade) could now dig in their heels (vis a vis India) and say no relaxation of controls," Ghosh said.

"The 45-member group is meeting in Geneva and I will be looking at comments coming out of there," she added.

The NSG approves the sale of nuclear equipment from other countries that India is hoping to trade with following the U.S. nuclear pact.