South Korea and Indonesia opened a joint program management office on Wednesday for development of the KF-X fighter aircraft.

Yonhap News Agency reports the office in the city of in Sacheon, southeast of Seoul.

"The opening of the joint program management office will not only help the two countries exchange views on pending issues during the KF-X project but also allow them to effectively fine-tune differences," Jung Kwang-sun, director general for the KF-X Program Group at the DAPA, said in a statement.

DAPA is South Korea's Defense Acquisition Program Agency.

The two countries signed a $7.1 billion agreement last year to jointly develop the KF-X/IF-X 4.5-generation fighter. The project is led by DAPA, with the Korea Aerospace Industries leading the development.

Indonesia's state-owned PT Dirgantara Indonesia has sent 74 engineers and officials to KAI to participate in the project.

Development of the fighter is currently in the preliminary design phase. A prototype of the jet is expected to take to the air in 2021 or 2022.

The report said South Korea requires more than 100 of the aircraft, which will replace the country's F-4 and F-5 aircraft. Indonesia needs at least 50 of the planes.