ANKARA, Turkey — Turkey’s defense procurement agency has named four local bidders for a critical contract that aims to combine all information systems on the country’s planned F-35 Lightning II jets to the Turkish Air Force’s system network.

The Undersecretariat for Defence Industries (SSM in its Turkish acronym) says the four are: military software specialists Altay Yazilim, Aydin Yazilim, Havelsan and Milsoft Yazilim.

Of the bidders, all but Havelsan are privately owned companies. Havelsan is a state-controlled entity.

“The local interest in the program is an indication of the government’s intention to make the combined system as indigenous as possible,” a procurement official said.

Under the program, the successful contender will connect the information systems installed on the F-35 fighter aircraft with the Air Force’s information systems network, otherwise known as HvBS.

“The program involves safe connection of information systems elements between the F-35 aircraft and the Air Force’s information systems network as well as safe sharing of classified information between these systems,” SSM said.

SSM’s department for cybersecurity and electronic warfare systems will be in charge of the program.

Turkey is a partner in the U.S.-led, multinational Joint Strike Fighter program. Under the JSF program, Turkey has committed to procure a total of 116 aircraft. Turkey placed its first JSF order in 2014 under its low-rate initial production 10 program, and its second order in October 2016.

Turkey’s procurement and military officials are hoping to build a new-generation, dual-fighter jet fleet by their country’s centennial, 2023, comprising of the F-35 and an indigenous aircraft, known as TF-X, that Ankara has been designing under a know-how contract with BAE Systems.

Industry sources said the program to build critical links between the F-35 aircraft and Turkey’s combined Air Force command network probably won’t cost hundreds of millions of dollars, but it was tagged as “strategic” by the procurement authority.

But some foreign observers remain cautious. “Naturally there will be limits to the Turkish work as part of this program,” according to a London-based aerospace specialist. “The Turks may not be able to go as far as they wish to.”