Onur Oymen, a Turkish member of parliament who once served as Turkey's permanent representative to Nato, says the Turkish government has evidence to prove that the Russian jet was flying over Turkey when it was shot down:

Moscow insists its plane never strayed from Syrian airspace.

Syrian Turkmen brigade deputy commander Alpaslan Celik tells Reuters:

The deputy commander of a Turkmen brigade in Syria says his forces shot dead two pilots of the downed Russian jet as they descended with parachutes, says Reuters.

Apologies, we earlier published a picture of what appeared to be the downing of the Russian jet provided by the AFP news agency. They have since said it was provided at another time.

Russia's defence ministry said the two pilots parachuted from the plane but added that Moscow had no further contact with them. Rebels said they fired at the pair as they ejected. Video footage has shown what appears to be the dead body of one of the flyers, surrounded by armed rebels.

Russia's consulate in Istanbul and the Turkish Embassy in Moscow have both seen protests.

Image source, AFP

Image source, AP

In another development, there are reports that a Russian military helicopter was forced to make an emergency landing after coming under fire from Syrian rebels. According to the Syrian Observatory for Human Rights, the aircraft managed to reach nearby government-held territory in the north-eastern Latakia region.

Turkish Prime Minister Ahmet Davutoglu has defended the shooting down of a Russian fighter jet, saying it was their "national duty to take any measure against whoever violates our air or land borders".

Image source, Reuters

Turkish officials say its foreign ministry has summoned US, Russian, French, Chinese and British envoys to brief them on the downing of the Russian jet, according to Reuters.

Mr Putin ended his speech by suggesting Turkey wanted Nato "to serve" IS. He earlier described the Turks as "accomplices of terrorists".

Mr Putin said: "We will analyse everything in detail and today's tragic events will have significant consequences including for relations between Russia and Turkey." 

Image source, AP

He said the aircraft was inside Syrian airspace - 4km from the Turkish border - when it was hit, news agencies report.

Russian President Vladimir Putin has called the downing of a Russian jet at the Turkey-Syria border "a stab in the back by the accomplices of terrorists". 

He was speaking live on state-owned TV channel Rossiya 24.

On the topic of Syria's crowded skies, here's a video explainer produced before today outlining the large number of countries operating in the area, adding to the risks of a dangerous encounter 

Famil Ismalov from the BBC Russian service gives his opinion on the shot jet to BBC World:

"It was bound to happen", he says. 

"We are talking about tight airspace and tight territory where the air raids were being conducted. 

  "Sooner or later the Russian planes would get into the Turkish airspace."  

Reza Afshar, a former UK Foreign Office official in charge of Britain’s policy on Syria tweets:

Sam Greene, director of the King's Russia Institute, external at King's College London, offers his insight on Putin's to-do list and how today's events figure in terms of priorities.

Here's the statement from the Russian Ministry of Defence website, external.

Image source, Russian Ministry of Defence

The website includes reports on the Russian air operation in Syria which it describes as a "retaliatory operation aimed at elimination of leaders of terrorist organisations and their allies, disruption of control and supply systems, as well as destruction of the ISIS military and oil and gas production facilities".