Bulgaria's Defense Ministry has asked the government to begin direct talks with the United States about purchasing F-16 fighter jets to replace its aging Soviet-designed MiG-29 warplanes.

The NATO member's ministry on December 21 said the "acquisition...will raise the combat capabilities of Bulgaria's air force to a new level."

Bulgaria's parliament on June 8 approved a plan to spend about $2 billion to purchase 150 combat vehicles and 16 new or used fighter jets.

About $1 billion was earmarked to cover the cost of the first eight aircraft, as well as team training and initial logistics support.

However, an initial offer by Lockheed Martin of the United States exceeded the figure.

"A lowering of the price, which according to them is doable, can only be achieved in direct government-to-government talks," Defense Minister Krasimir Karakachanov told a news conference.

Bulgaria joined NATO in 2004, but the question of which warplanes to buy to replace the MiGs has vexed successive governments for more than a decade.

NATO has encouraged its eastern members to develop or buy new equipment from Western alliance members to replace their older Soviet-era systems.

Several Bulgarian Air Force pilots in 2017 refused to fly their Soviet-built MiG-29 jets in planned training exercises, citing safety concerns with the outdated aircraft.

Conservative Prime Minister Boyko Borisov has said he favors the F-16 fighters over other offers, which include Boeing F-18s, Gripen fighters from Sweden, and used Eurofighters from Italy.

The Defense Ministry also asked the government to seek approval in parliament for a larger budget should it not be able to attain a discount from Lockheed Martin.

Based on reporting by AFP and Reuters