A C-17 Globemaster plane drops paratroopers during an exercise over the NATO airbase in Aviano, northern Italy, March 22, 2011. [Photo/Agencies]

NEW DELHI - India has approved its biggest defense deal with the United States for 10 Boeing C-17 strategic heavy-lift planes for $4.1 billion, reported local media Tuesday.

The Indian cabinet committee on security chaired by Prime Minister Manmohan Singh Monday gave its nod for the deal to equip the Indian Air Force (IAF) with the aircraft, reported Indo-Asian News Service.

The clearance came six months after US President Barack Obama visited India and two months after Boeing and Lockheed Martin were knocked out in bidding for a $10.4 billion deal for 126 combat jets for the IAF.

The US Congress had approved the sale of the fully loaded aircraft for $5.8 billion under the Foreign Military Sales government-to-government route last June.

However, since India is yet to ink a key military pact with the US, the aircraft might come without some critical communications equipment.

India is yet to sign the Communication Interoperability and Security Memorandum of Agreement (CISMoA), a pact mandated by the US law for the transfer of hi-tech military equipment to friendly countries.