With Russian warplanes making regular forays over Syria to carry out airstrikes against insurgents, several presidential candidates are calling on the United States to respond militarily by setting up a no-fly zone in the country.
Republicans have led the charge, with Gov. Chris Christie of New Jersey even saying he would shoot down Russian jets.
19:16 Analysis: Why are Russian warships in British waters?
12:28 Syrian army and Russian jets halt Aleppo bombardment for second day1
22:36 Wary of Russian Guarantees, Residents Stay Put in War-Torn Aleppo
14:04 Turkey unleashing fury of airstrikes against US-backed Syrian Kurdish forces