WASHINGTON: The US State Department has approved the possible sale of eight F-16 aircraft and related equipment to Bulgaria at an estimated cost of $1.67 billion, a Pentagon agency said on Monday.

The prime contractor will be Lockheed Martin Corp, the Defense Security Cooperation Agency said in a statement.

"The proposed sale will contribute to the foreign policy and national security of the United States by helping to improve security of a NATO ally and a key democratic partner of the United States in ensuring peace and stability in this region," the statement said.