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By Bappa Majumdar

NEW DELHI, July 5 (Reuters) - A key regional party in India said on Saturday that a controversial nuclear energy deal with the United States was in the interest of the nation, easing concerns the pact could trigger early elections.

Support from the Samajwadi Party (SP) is likely to help the Congress Party-led government secure a parliamentary majority if communist parties carry out their threat to withdraw support in protest at the nuclear deal.

"We will not vote against the government, even if the communists and other parties do," Amar Singh, the SP general secretary, told reporters in New Delhi.

"The deal is in the interest of the nation, we should have come out in support of the deal a year ago," he added.

The Samajwadi Party has 39 seats in parliament, compared with 59 for the communist parties. The Congress-led ruling coalition needs the support of 44 lawmakers to reach a majority. It would try to win the other five seats from smaller parties.

The left parties object to the nuclear deal, saying the nuclear pact will make India a pawn of Washington.

The pact will give India access to U.S. nuclear fuel and technology, and is potentially worth billions of dollars to U.S. and European nuclear supplier companies. It will also give India more energy alternatives to drive its development, shifting trade and diplomatic ties towards the West.

The SP has a history of pragmatic alliances with national parties, but it said that they had buried years of bitter relations and described the Congress party as a "secular force".

"In politics, parties switch sides often, but we never sided with communal forces," Singh said. "The Congress is definitely a secular force and we have always stood by and will stand for secular forces."

Singh said SP leaders met former President A.P.J. Abdul Kalam, seen as the father of India's missile programme, this week and they were satisfied with his views the deal could benefit India.

"He (Kalam) told us that India has a shortage of uranium and India does not need to test anything now, I think what Kalam said is correct," Singh said.

With time fast running out, the government needs to seek approval for the deal from the International Atomic Energy Agency (IAEA), the next international move needed to make the agreement operational.

The political uncertainty coupled with high oil <CLc1> prices and a 13-year high inflation <INWPI=ECI> hit investors' sentiments and shares <.BSESN> dropped 2.5 percent in the past week.

(Editing by Jeremy Laurence)

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