He said: “There can be only one answer to Putin’s aggression. Unity in Nato and a credible deterrent.
“This in particular means there is no alternative but to choose the F35s.”
Unlike Britain, France and the US, Germany does not have nuclear weapons of its own.
However, it has maintained bombers with the capability to carry US nuclear weapons as part of a system of nuclear deterrence from the Cold War.
The new F-35s will replace the ageing Tornado planes which are currently the only German aircraft that have the capability to carry nuclear weapons.
Previously, before the Ukraine crisis the government had considered replacing the Tornado’s with a mixture of US and European made aircraft.
US Ambassador Amy Gutmann said that by buying the new aircraft Germany was “cementing its continued participation in Nato’s nuclear-sharing mission”.
Germany Defence Minister Christine Lambrecht announced that Berlin will also upgrade its Eurofighter Typhoon fighter jets.
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Ms Lambrecht was adamant, however, that FCAS is no danger of falling through reaffirmed Germany’s commitment to it.