Germany says it doesn't believe Assad regime can continue as Syria's leader under a future peace agreement.

Foreign Ministry spokesman Martin Schaefer says that Assad's forces capturing eastern Aleppo and other parts of northern Syria "strengthens the regime" and its hand in political negotiations.

But Schaefer told reporters in Berlin on Monday that Germany's assessment that "Assad can't play a permanent role in a peaceful future for Syria" hasn't changed now that his forces are blamed for over 300,000 deaths in the six-year war.

Schaefer said opposition groups wouldn't accept any deal to form a transitional government unless Assad's powers were sharply curtailed.