Zabiullah Mujahid, a Taliban spokesman, said in a statement, "We strongly condemn" Germany's decision "to prolong its occupation as well as the killing and oppression of the persecuted Afghan nation," Khaama Press reported.
He cautioned Germany's continued involvement in "America's war of fancy" would cause the Taliban to "take a harsh stand against it by targeting it with special tactical and jihadi operations which will force them to regret their illogical decision."
The German government, which has the third-largest deployment of foreign troops in Afghanistan, announced Thursday it would keep 800 military trainers in the country after NATO combat operations end in 2014.
It has 4,200 soldiers in Afghanistan, down from an initial deployment of more than 5,000.
NATO plans to keep 8,000 to 12,000 troops in the country after 2014 to train and assist the Afghan army.