On a letter dated Sept. 4, a copy of which was obtained by The Jakarta Post, Tanner said she wanted to enter into specific sales negotiations with her Indonesian counterpart Prabowo Subianto, Austrian newspaper Kronen Zeitung reported on Sunday.

She also thanked Prabowo for his interest in buying a fleet of 15 Eurofighter Typhoon jet fighters.

"The Austrian Armed Forces are facing major challenges in air surveillance in the coming years,"  Tanner said in the letter, which was written in German. 

"We are, therefore, happy to accept your interest in purchasing the 15 Austrian Eurofighters to modernize your air fleet and will now evaluate and examine this intensively.

“In this regard, my experts will contact your positions to clarify further detailed questions.”

Tanner was replying to a letter from Prabowo offering to buy the Typhoons.

“To achieve my target of modernizing the Indonesian Air Force, I would, therefore, like to propose to enter into official deliberation with you, your Excellency, on purchasing all 15 Eurofighter Typhoons from Austria for the Air Force of the Republic of Indonesia,” Prabowo said in a letter dated July 10.

Prabowo's letter sparked controversy as it was the first official offer known to the public on a possible acquisition of fighter jets.

Earlier this year, news broke that Indonesia would buy Dassault Rafale fighter aircraft from France following Prabowo’s visit to the country in January.

French newspaper La Tribune reported that Indonesia was interested in procuring 48 Rafale jets in addition to two Scorpene submarines and two Gowind corvettes.

There was, however, no official correspondence in the possible acquisition of the French weapon systems.

Lawmakers and defense observers opposed the plan to purchase Austrian Typhoons because they were considered old, having been procured in a 2002 contract worth 2 billion euro (US$2.28 billion), and not advanced enough as a Tranche 1 focusing on air-defense missions. The first aircraft was delivered in 2007.

It was also pointed out that buying Austrian Typhoons would violate Law No. 16/2012 on the defense industry, which mandates foreign weapon purchase to come with some kind of countertrade, local content and offset schemes.

Another contention was that Indonesia is currently working to make its own fighter jets by securing a 20 percent share in South Korean’s KF-X program, which Indonesia joined in 2010. 

Korean Aerospace Industries (KAI) is working with PT Dirgantara Indonesia to design and manufacture the jets, in which Indonesia is projected to buy 48 aircraft while South Korea is slated to buy 120. 

The KF-X jet fighter will have its first rollout in 2021 and the first flight is scheduled for 2022, The Korea Herald reported on July 8.  

On Sept. 3, KAI revealed that parts of the first prototype consisted of the fuselage and wings. 

In its report, Kronen Zeitung said the letter would be sent to Prabowo's office through the Indonesian Embassy in Vienna.

The Indonesian Embassy, however, said on Sunday that it had yet to receive the letter.

WhatsApp messages sent to Defense Ministry spokesman Brig. Gen. Djoko Purwanto and Prabowo spokesman Dahnil Simanjuntak went unanswered.