WASHINGTON: The Pentagon on Friday said it had finalized two contracts with Lockheed Martin Corp valued at $7.8 billion for 71 more F-35 fighter jets, citing what it called significant reductions in the cost of new radar-evading warplane.

The Defense Department said it signed a $4.4 billion contract for a sixth batch of 36 F-35 aircraft, with the average cost of the planes down 2.5 percent from the previous deal.

The two sides also signed a $3.4 billion contract for 35 aircraft in a seventh batch, which reflected a 6 percent drop in the average price from the fifth batch, it said in a statement.

The Pentagon said the cost of each F-35 conventional takeoff A-model jet would drop to $98 million in the seventh batch of jets, excluding the engine. The government buys the engines directly from Pratt & Whitney, a unit of United Technologies Corp, under a separate contract.