TIMELINE: Twists and turns in the India-U.S. nuclear deal

(Reuters) - Prime Minister Manmohan Singh appears to be pressing ahead with a civilian nuclear deal with the United States despite threats from his communist allies that they could withdraw their crucial parliamentary support from the government.

Here is a timeline of some key developments over the past three years:

* July 2005: Prime Minister Manmohan Singh and U.S. President George W. Bush agree in principle to a landmark civilian nuclear cooperation deal. The deal reverses 30 years of U.S. policy opposing nuclear cooperation with India because it developed nuclear weapons in contravention of global rules and never signed the Non-Proliferation Treaty, or NPT.

* March 2006: Bush pays a three-day visit to India during which the two countries agree on India's plan to separate its civilian and military nuclear reactors, a key requirement for the deal to go through.

* December 2006: U.S. Congress overwhelmingly approves the deal. Three other approvals -- from the 45-nation Nuclear Suppliers Group, the International Atomic Energy Agency (IAEA) and a second time by the Congress -- are still needed before nuclear transfers to India can actually take place.

* December 2006: Bush signs the law approved by Congress, which makes changes to the U.S. Atomic Energy Act. Analysts say the deal could be fully approved in roughly six months.

* July 2007: The two countries announce finalization of the deal after months of tough negotiations on a bilateral pact. India had objected to what it said were new conditions in the agreement unacceptable to it.

* August 2007: Text of the bilateral pact, called the 123 agreement, is unveiled simultaneously in both countries. Indian analysts say it meets most of New Delhi's demands, but communist allies of the government coalition threaten to withdraw support over the pact, saying it compromises India's sovereignty. Singh defends the deal as crucial to India's prosperity.

*October 2007: Fraught meetings between the left and the coalition government take place after Sonia Gandhi, head of the Congress party, describes opponents of the deal as enemies of development. A snap election is averted after the government agrees to delay approaching the IAEA.

*November 2007: The left briefly softens its position and allows the government to begin talking to the IAEA about the safeguards agreement India needs to clinch the deal. But later in the month, communist politicians accuse the government of misleading the country.

*December 2007: Communists tell the government to stop talking to the IAEA.

*February 2008 - The U.S. urges India to close the deal before Bush leaves office, saying the deal was unlikely to be offered again under the new administration.

*June 25: The coalition meets with its leftist allies to try and resolve the impasse, but no agreement is reached.

*July 1: The Communist Party of India (Marxist) says it is discussing the timing of its withdrawal of support, saying the government appeared to be pressing ahead with the deal.

*July 4: The left give the government a July 7 deadline to decide whether it is going ahead with the deal.

(Compiled by Jonathan Allen; Editing by Alistair Scrutton and Alex Richardson)

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