Germany will replace most ageing Tornado fighter-bomber jets in its air force fleet with Eurofighter aircraft but buy a share of the replacements from US manufacturer Boeing, media reported Friday.

From 2025, the Tornados will be replaced by up to 90 Eurofighters built by Airbus and 45 Boeing F-18s, according to news weekly Der Spiegel.

A defence ministry spokesman told AFP the final decision on the fighter jets would be made "in the coming days".

The solution straddling two aircraft would allow Germany to reaffirm its commitment to joint defence projects with European partners without raising hackles in Washington or at NATO headquarters.

Some of Berlin's existing Tornado fleet are certified by the US to carry American nuclear weapons.

In turn, some of the new F-18s will be outfitted so Germany's Luftwaffe (air force) remains capable of such missions, Der Spiegel reported.

Eurofighters will replace most, but not all, of Germany's Tornados
Eurofighters will replace most, but not all, of Germany's Tornados AFP / Ina FASSBENDER

The magazine cited a German federal auditors' report describing the 1970s-era Tornado as a "weapons system that has become obsolete, increasingly marked by technical faults and lack of availability."

While buying F-18s should placate the US on the nuclear issue, ministers will be hoping their mass Airbus purchase also quashes questions about a key future European defence project.

The French and German defence ministers signed in late February a 150-million-euro ($164 million) contract to develop the first prototype of a European jet dubbed the Future Combat Air System (FCAS).

February's accord put an end to months of squabbles over whose defence firms should take the lead on different components, with the German side particularly afraid of losing its edge to project leader France.

After the prototype is delivered -- slated for 2026 -- the new planes should replace present fleets of German Eurofighters and French Rafales in the following decades.

Spain is also keen to jump aboard the FCAS project, especially on the research side.