ST.PETERSBURG, Russia (AP) — Russia's foreign minister has strongly warned that an international conference intended to negotiate peace for Syria could be derailed if the U.S. decides to push for a no-fly zone over the country.

Sergey Lavrov, speaking in an interview with The Associated Press and the Bloomberg news agency on Friday, also warned against pushing the demand for Syrian President Bashar Assad to step down, calling it unrealistic. He accused the West of sending conflicting signals to the Syrian opposition, encouraging rebels to keep fighting.

He said that supplies of weapons to the Syrian opposition promised by Washington and under consideration by the EU would be a "very big mistake."

A time and place for the international conference on Syria hasn't been announced yet.