The world's biggest aircraft manufacturers are in the race to supply the Indian air force with 126 new fighter jets in a deal worth an estimated $10 billion. As Anjana Pasricha reports from New Delhi, this will eventually be one of India's largest defense purchases. 

Six aircraft manufacturers from Russia, the United States and Europe have been invited by the Indian Defense Ministry to bid for the aircraft contract. 

The jets being considered are Lockheed Martin's F16 and Boeing's F18 from the United States, Russia's MIG-35, the Dassault Rafale from France, Sweden's JAS-39 and the Eurofighter Typhoon, which is produced by a consortium of European firms.

India wants to modernize its air force, whose fleet is mostly made of aging Russian MIG fighters, as well as French and British aircraft.   

Defense analysts say fighters produced by Russia and U.S. companies are the frontrunners in the race.

India has never purchased fighter planes from American companies before, but ties between India and the United States have warmed in recent years. 

Rahul Bedi of Jane's Defense Weekly says the new equation between India and the U.S could influence the ministry's final selection.  

"Ultimately it is going to be not only an equipment-based decision, but it is also going to be a political decision, so India's increasing ties - strategic ties - with Washington are going to play a fairly significant role in deciding the outcome of this deal," he said.

Bedi says poor service the Indian military has encountered with Russian purchases in the past might also persuade it to turn away from its traditional dependence on Russian hardware.     

"The Indian air force is quite exasperated and frustrated with Russia, because of back-up and supplies and logistics once the sales are made," he added.  "There is a problem, so it is quite possible India may shift away from its traditional supplier, but again it is very difficult to say at this stage, because the Russian MIG-35 which is in competition with the other vendors is also very competent."

Under India's proposed terms, the first 18 planes are to be bought off the shelf.  The remaining aircraft are to be manufactured in India under a technology licensing arrangement. 

The entire deal is estimated to be worth about $10 billion, but nobody is counting the money yet.  Deals like this are not completed quickly, and ministry officials have indicated it could still be years before the supplier is chosen.