India has invited initial bids, estimated to be worth up to $2 billion, from global helicopter companies to supply its air force with 22 combat helicopters and another 15 for heavy-lift duties, a senior official said Tuesday.

"The two (separate) requests for proposals have been issued," the senior air force official, who didn't wish to be named, told Dow Jones Newswires late Tuesday. The official declined to elaborate or name the companies that had been invited to bid.

Attack helicopter makers such as Russia's Kamov and Mil Moscow Helicopter Plant, Italy's AgustaWestland, a unit of Finmeccanica SpA (FNC.MI), and Textron Inc.'s (TXT) Bell Helicopter unit had earlier expressed interest in the deal.

Eurocopter, the helicopter manufacturing unit of European Aeronautic Defence & Space Co. (EADSY), too, has pitched its Tiger attack helicopter for the tender while Boeing Co. (BA) is offering its Apache AH-64D Longbow model.

Boeing's India unit confirmed that it has been invited for both the tenders.

Officials at the other companies weren't immediately available for comment.

"We have received both requests for proposals and our rotorcraft division is reviewing them," Vivek Lall, who heads Indian operations at Boeing's Integrated Defense Systems division, told Dow Jones Newswires via telephone.

This is the second time India has issued a tender for the attack helicopters. The first tender - issued in May 2008 - was scrapped in March by the government.

Both Boeing and Bell helicopter had pulled out of the original tender, as the Indian Air Force wanted to buy directly from the manufacturer, but the U.S. wanted it to be a government-to-government deal, defense ministry officials had said earlier.

Boeing also is pitching its heavy-lift, twin-rotor Chinook helicopter. Analysts value the potential deal as ranging from $600 million to $1 billion.

Sikorsky Aircraft, a unit of United Technologies Corp. (UTX), also plans to bid to sell heavy-lift helicopters, its India and South Asia managing director, A.J.S. Walia, said in February.

 
   -By Nitin Luthra, Dow Jones Newswires; +91-11-4356-3306; nitin.luthra@dowjones.com