Germany's Defense Ministry has warned of potential risks in the €10 billion ($10.5 billion) deal to buy F-35 fighter jets from the US, according to a local media report.
Berlin plans to purchase 35 of the warplanes made by Lockheed Martin, with the first eight jets scheduled for delivery in 2026.
While the Biden administration approved the sale of the jets, munitions, and associated equipment in July, Germany reportedly has until the end of year to finalize an agreement with Lockheed Martin.
However, in a classified letter to the German parliament's budget committee, the Defense Ministry raised concerns over soaring costs and technical problems.
It said the security requirements of the US are extremely complex, so "delays and additional costs before the start of flight operations cannot be ruled out," according to German daily Bild.
The ministry said it remains uncertain whether the necessary upgrades at Buchel Air Base in southwestern Germany, where the jets are supposed to be located, could be completed by 2026, the report said.
The letter also pointed to other factors that could increase costs, including inflation, exchange rate fluctuations, and higher production costs.
Under Chancellor Olaf Scholz, Germany has embarked on a military spending drive and indicated repeatedly that it wants to take up a leading security role in Europe in the wake of the Ukraine war.
The F-35 fighter jets are meant to replace Germany's aging fleet of Tornado nuclear-capable bombers by 2030.
