Putin has said that the Su-24 jet was carrying out operations in northern Latakia province against IS militants, including "those from the Russian Federation."
There are two main Chechen-led groups in northern Latakia province, both of them small -- and neither have any links to the IS group.
The groups are Ajnad al-Kavkaz ("Soldiers of the Caucasus"), a small group of veteran Chechen militants led by a Chechen from Grozny named Khamzat Azhiyev or Abdul Hakim Shishani. His group is independent but has fought alongside Syrian Islamist factions including Syria's Al-Qaeda affililate the Al-Nusra Front.
The second group is Junud al-Sham, another group of veteran militants led by Murad Margoshvili a.k.a. Muslim Shishani. That group has also fought alongside the Al-Nusra front but in recent months has run a training camp in northern Latakia, sources in Syria say.
Both these groups consists of tens of fighters.
In addition, there are two other tiny Chechen factions in northern Latakia.
Putin claimed that these militants could "return to Russia at any moment." The majority of the North Caucasian militants in Latakia are fighting in Syria because they have been unable to return to Russia, since they are on FSB wanted lists. Sources in Syria say that some of Ajnad al-Kavkaz's militants are not on wanted lists, however -- but this is impossible to confirm.
This is Putin's full statement as reported by RIA Novosti:
"They [the jet] were carrying out operations in the fight against IS, northern Latakia -- that is a mountainous region, where militants are concentrated, mainly those from the Russian Federation. In this sense they were carrying out pre-emptive strikes against terrorists, who at any second, at any time could return to Russia."
Russia's Defense Ministry added in a tweet that "analysis of objective control data unambiguously shows that there had been no violation of Turkish air space."
Russia's Defense Ministry has just now tweeted that the Russian Su-24 jet was shot down by Turkish F-16 fighters as it was flying back to the Hmeymim air base.
Earlier, Russia had said the jet was shot down by surface to air fire.
The tweet says, "The Russian war plane Su-24 was shot down by a Turkish F-16 fighters in Syrian territory during its return to the Hmeymim air base."
RIA Novosti has more details of Putin's comments on this morning's downing of a Russian Su-24 jet in Syria.
Putin says that the jet was attacked in Syrian territory, one kilometer from the border with Turkey and landed four kilometers from that border.
The jet did not threaten Turkey, Putin said.
Putin also said that the jet was hit by an "air to air" missile, which is different from initial Russian comments on the downing. Earlier today, the Russian Defense Ministry said the plane had been hit by ground fire.
"Our plane was hit on Syrian territory by an "air to air" rocket from a Turkish F-16. It fell on Syrian territory four kilometers from the border with Turkey. It was in the air when it was attacked, at an altitude of 6,000 meters at a distance of one kilometer from Turkish territory. In any event, our pilots and our plane did not in any way threaten Turkey," Putin said.
Turkey's Prime Minister Ahmet Davutoglu says that his country has the "right to respond" if its air space has been violated, Reuters has just reported.
More from Putin on the downing of the Su-24 in Syria today.
The Guardian's Shaun Walker says the Russian President looked furious as he talked about the incident.
RFE/RL's Radio Svoboda is reporting that Putin has said the downing of the Su-24 will have "tragic consequences for Russian-Turkey relations."
Russian President Vladimir Putin has said that Russia is "reviewing everything that happened with its plane in Syria," RIA Novosti has just reported.
This item's just in from RFE/RL's Georgian Service:
TBILISI -- Georgia has launched an investigation into an Islamic State video purportedly showing Georgian-speaking men fighting alongside IS militants in Syria.
The State Security Service announced the probe on November 23, a day after the twelve-and-a half-minute-long video circulated on the Internet. In the recording, four Georgian-speaking men, holding AK-47 rifles and an RPG grenade launcher, call on Muslims in Georgia to join the "Caliphate."
The men slammed Muslim clerics in Georgia's Muslim-populated region of Ajara and threatened to behead "infidels" in Georgia.
Georgian media identified the men as former residents of Ajara, which is located in the southwestern corner of Georgia on the Black Sea.
Georgian officials have said that dozens of Georgian nationals have joined Islamic militants in Syria and Iraq.
Among them is Tarkhan Batirashvili, also known as Umar al-Shishani, a notorious battlefield commander in northern Syria.
More developments from Turkey via AFP.