A Russian pilot who went missing after his jet was shot down by Turkey while taking part in air strikes over Syria was rescued in a 12-hour operation involving special forces, Russia says, reports BBC.The pilot is "alive and well" at a Russian air base in Syria, it says.His co-pilot and a marine involved in a failed rescue attempt were killed.Turkey said the jet had strayed into its airspace but Russian President Vladimir Putin says the plane was flying over Syrian territory.It is not clear what has happened to the body of the other pilot, who was killed by gunfire as he parachuted from his burning plane.Tensions have escalated between Russia and Turkey over the incident, but the US, the EU and the UN have all appealed for calm.President Putin has described the downing of the plane as a "stab in the back", and warned of serious consequences.Turkey`s President Recep Erdogan has defended the action, saying "everyone must respect the right of Turkey to protect its borders", but he stressed he did not want to escalate tensions further.Turkey is a member of Nato. The alliance has backed Turkey`s version of events, although it, too, is calling for "diplomacy and de-escalation" to resolve the situation.