Analyst: More violence to come in Turkey 03:00
(CNN)A police officer assassinated Russia's ambassador to Turkey at an art exhibition in Ankara on Monday, officials said. The gunman shouted "Do not forget Aleppo!" as he opened fire.
The shooting of Ambassador Andrey Karlov was captured on video. Russia's foreign ministry described it as a "terror attack."
Russia has been instrumental in helping Syrian President Bashar al-Assad's regime in its push to retake the eastern sector of Aleppo, which had been held by rebels for nearly four years.
Here's what we know right now:
• Russian President Vladimir Putin called the assassination a "provocation," vowing to step up security at diplomatic missions. "This murder is clearly a provocation aimed at undermining the normalization of Russia-Turkish relations as well as at undermining the peace process in Syria promoted by Russia, Turkey, Iran and other countries interested in promoting settling the crisis in Syria," Putin said in televised remarks. "The only response we should offer to this murder is stepping up our fight against terror, and the criminals will feel the heat."
• Turkish President Recep Tayyip Erdogan said the killing won't dampen the two countries' efforts to build a stronger relationship. "We know that this is a provocation on destroying the relationship between Turkey and Russia during this normalization process. ... All the expectation of what they want to achieve with this attack will be in vain and never happen," Erdogan said in televised remarks Monday.
• Police officer Mevlut Mert Altintas was the gunman, Turkish Interior Minister Suleyman Soylu said in a press conference. The attacker was born in 1994 in the town of Soke in Turkey's Aydin province, he said. CNN initially reported the officer was was off-duty at the time of the shooting, but Turkish government statements left his duty status Monday unclear.
• Turkey's official Anadolu news agency reported that the gunman had been neutralized. But it was not immediately clear whether the attacker was killed or captured by police.
• Karlov was giving a speech at the opening ceremony of a photo exhibit when the gunman opened fire.
• Images of the scene showed a body on the ground as a man wearing a suit and holding a pistol stood nearby.
• In a video circulating on social media that shows the shooting, the gunman is heard shouting, "Allahu akbar (God is greatest). 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.
• The shooting occurred a day before diplomats from Turkey, Iran and Russia are scheduled to meet in Moscow to discuss the situation in the besieged Syrian city of Aleppo.
Emergency vehicles respond to the shooting of the Russian ambassador to Turkey.
• "We are currently in contact with Turkish authorities, who are assuring us that a thorough, comprehensive investigation will be conducted," Russian foreign ministry spokeswoman Maria Zakharova said in remarks broadcast on Russian television. "Murderers will be punished. Terrorism won't sustain. We'll fight it."
• "This attack shows the most disgusting and barbaric face of terrorism," Turkey's foreign ministry said, vowing to fight terrorism alongside Russia and its other allies.
• The attack occurred at the Cagdas Sanat Merkezi modern arts center in Ankara. The arts center is located in a posh, upper-middle-class neighborhood, near luxury hotels and many foreign embassies.
• Russia's 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.
• Putin and Erdogan spoke on the phone after the shooting to discuss the details of Karlov's death, according to Russia's state-run Sputnik News Agency.
Focus on Aleppo
Russia is the most powerful ally of Assad's regime and has carried out airstrikes since September 2015 to prop up the embattled leader. As one of the five permanent members of the UN Security Council, Russia has also used its veto powers to block a political solution to end the war.
"Our task is to stabilize the legitimate government and to create conditions for a political compromise ... by military means, of course," Putin told the state-run Russia 24 TV in September.
Moscow's bombardment of Syria has drawn criticism from Western powers, with US President Barack Obama on Friday accusing Russia of slaughtering civilians in the besieged city of Aleppo.
"Responsibility for this brutality lies in one place alone: the Assad regime and its allies Russia and Iran," Obama said during a year-end news conference. "The blood for these atrocities are on their hands."
Moscow has recently tried to distance itself from the current assault in eastern Aleppo, saying earlier this month it hasn't bombed the city since October 18.
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
In its statement after Monday's shooting, Turkey's foreign ministry said it wouldn't let the attack cast a shadow on the friendship between Turkey and Russia.
The attack comes at a time of improving relations between the two countries -- 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.
Erdogan meets with Putin after weeks of tension 03:00