Russian military will strike groups violating Syrian ceasefire

The Defense Ministry in Moscow said Tuesday said that the Russian military stood ready to strike groups that it said were violating the cease-fire unless US leaders agree to discuss a Russian proposal for how to maintain the peace. So far, Russian warplanes have been observing the cease-fire, US officials say.

Secretary of State John Kerry is due to meet Thursday with Russian leaders in Moscow to discuss efforts to achieve peace in Syria.

Russia's Defense Ministry later announced it was flying up to 25 sorties a day to support the Syrian army's efforts to retake Palmyra from the Islamic State, which is permitted under the terms of the cease-fire.