A Puma tank crosses a river during a German army training and information day in Munster, October 9, 2015. REUTERS/Fabian Bimmer

The German military has had its eyes on a new infantry fighting vehicle for some time.

The vehicle, called the Puma, is supposed to replace the aging Marder infantry fighting vehicle.

But federal auditors say development issues could add years to the Puma's arrival date.

The German military is in the process of adding the new Puma infantry fighting vehicle to its fleet to replace the aging Marder, which has been in service since 1971, but federal auditors say the program could soon by hit by yearslong delays.

The Puma and the Marder both have a crew of three, though the Puma carries just six troops to the Marder's seven. But the Puma packs more firepower, including a 30 mm cannon, an upgrade from the Marder's 20 mm cannon, as well as a 5.56 mm coaxial machine gun and an anti-tank guided-missile system.

The Puma also incorporates composite armors that can better withstand modern weapons, including improvised explosive devices (IEDs) and explosively formed projectiles, and are lighter than older kinds of armor.

Overall, the Puma is about 6 tons heavier than the Marder, but the Puma has modular armor that can be removed to lighten it for air transport or added to increase its protection. The Puma can cover 373 miles on a single tank of gas and hit a top speed of 43 mph.

The first preproduction models of the Puma were delivered in 2004, and it was approved for service with the German army in April 2015.

German soldiers from the 41st mechanized infantry brigade perform an exercise with Marder infantry fighting vehicle in Viereck, Germany, July 16, 2015. REUTERS/Axel Schmidt

The German firm Rheinmetall, which is developing the Puma with Krauss-Maffei Wegmann, announced the delivery of the 200th vehicle this week, and the Bundeswehr wants to have 320 Pumas by 2020 to serve alongside its Leopard tanks.

But officials from Germany's Bundesrechnungshof, which is like the US Government Accountability Office, have said the Puma program's uneven progress and low availability rates mean German troops should be ready to use the Marder for years beyond the planned end-of-service date in 2025, according to Defense News.

Auditors acknowledged that the Puma program was only in the initial-delivery phase and was still dealing with growing pains. But they noted deployment-readiness rates of 48% in 2016 and 43% in 2017 and cited reports from the army that the Pumas did not have "system stability" and often experienced malfunctions during training.

Auditors said that based on similar programs in the past, it could take until 2029 to add all the Puma's required features. The anti-tank guided-missile system the Puma is supposed to be equipped with, for example, could be delayed for a year, from March 2019 to the second quarter of 2020.

A German Puma infantry fighting vehicle. US Army

Germany's Defense Ministry is working on several programs to upgrade the Puma and retrofit ones it already has, according to Defense News, but the ministry has told German lawmakers that some critical systems are still not online - and the cost for capabilities still to be added could be hundreds of millions of euros.

Federal auditors recommended a number of steps for the German army to prepare to keep the Marder in service past 2025, including stockpiling spare parts.

But the German military has struggled with that. Many of its weapons systems - like the Leopard 2 tank and the Typhoon and Eurofighter fighter jets - have been deemed unsuitable for operations or forced out of service because of maintenance issues in recent years, hindering readiness.

The Bundesrechnungshof delivered its findings to lawmakers as part of a series of reports to inform ongoing budget debates in the German parliament.

German's military budget has fallen considerably since the end of the Cold War, and Berlin is now looking to boost it, amid increased tensions between NATO and Russia and scoldings by President Donald Trump about European countries' levels of military spending.

The military budget has become one of the first internal disputes for the new coalition government headed by Chancellor Angela Merkel, which took office in March.

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