European Union foreign ministers are debating whether to extend sanctions against the Syrian regime as political efforts to secure a cease-fire falter.

EU foreign policy chief Federica Mogherini said Monday that ministers could add more Syrians accused of rights abuses or war crimes to the sanction list, saying "for sure, that could be possible."

But she said no EU country has raised the idea of imposing sanctions on Russia, despite its support for President Bashar Assad in his offensive on the besieged city of Aleppo.

Talks involving Russia, the U.S. and other Western powers over the weekend failed to secure any breakthrough likely to lead to a cease-fire or the opening of humanitarian access.