A gunman assassinated Russia's ambassador to Turkey on Monday, shouting "Allahu akbar" as he opened fire on Andrey Karlov at an art exhibition in Ankara.
Russia's foreign ministry described the shooting, which was captured on video, as a "terror attack."
"We are currently in contact with Turkish authorities, who are assuring us that a thorough, comprehensive investigation will be conducted," foreign ministry spokeswoman Maria Zakharova said in remarks broadcast on Russian television. "Murderers will be punished. Terrorism won't sustain. We'll fight it."
Here's what we know right now:
• Karlov was giving a speech at the opening ceremony of a photo exhibit when an assailant opened fire.
• Images of the scene showed a body on the ground as a man with a pistol stood nearby. In a caption, The Associated Press news agency described the man with the gun as the attacker. CNN has not independently confirmed the identities of the people in the photograph.
• In a video circulating on social media that shows the shooting of the ambassador, the gunman is heard shouting, "Allahu akbar (God is great). Do not forget Aleppo! Do not forget Syria! Do not forget Aleppo! Do not forget Syria!"
"Get back! Get back!" the man can be heard shouting in Turkish as he waves a gun.
"Only death will remove me from here. Everyone who has taken part in this oppression will one by one pay for it," he said.
• Authorities haven't said who they believe was responsible for the attack.
• Anadolu reported that the gunman had been neutralized. But it was not immediately clear whether the attacker was killed or captured by police.
• The attack occurred at the Cagdas Sanat Merkezi modern arts center in Ankara.
• The foreign ministry described Karlov as an "outstanding diplomat."
"He's a diplomat who's contributed a lot in fighting terrorism during his career," Zakharova said.
The ambassador began his diplomatic career in 1976 and has been the envoy to Turkey since 2013, according to a profile on the website for the Russian Embassy in Ankara.
A series of attacks
The shooting of the ambassador is the latest in a long string of attacks in Turkey this year, although it's the first in recent memory to be directed at a foreign dignitary.
A car bomb exploded near a public bus in the central province of Kayserion Saturday, killing 13 soldiers and wounding 55 people, according to Turkish officials.
The attack came exactly a week after a pair of bombings in Istanbul killed 44 people, including 37 police officers, and injured 155 others. The explosions, which occurred after a heavily attended soccer game at Besiktas Vodafone Arena, were claimed by a Kurdish militant group called the Kurdish Freedom Hawks.
Turkish-Russian relations were improving
The attack comes at a time of improving relations between Turkey and Russia -- relations that hit an all-time low after Turkish forces shot a Russian warplane out of the sky near the Syrian border in November 2015.
Russia had slapped a raft of sanctions on Turkey in the wake of the deadly jet incident, hurting Turkish exports and damaging its tourism industry.
But the relationship began to thaw in June when Turkish President Recep Tayyip Erdogan wrote a letter expressing "regret" to the family of the pilot who was killed in the shootdown.
When Erdogan faced down an attempted military coup in July, Russian President Vladimir Putin was among the first world leaders to call and offer his support.
Erdogan and Putin have spoken several times on the phone in recent weeks as they worked to hammer out a deal to evacuate civilians from rebel-held eastern Aleppo in Syria.