Russia’s ambassador to Turkey, Andrey G. Karlov, was killed by a gunman on Monday in Ankara, the capital.

Turkish officials said the killer had been a police officer who, after shooting, shouted: “Don’t forget Aleppo! Don’t forget Syria!” Russia’s Foreign Ministry called the assassination a terrorist attack.

Here’s what we know about Mr. Karlov.

What was his background?

• Mr. Karlov had been Russia’s ambassador to Turkey since July 2013, according to a biography on the website of the Russian Embassy.

• Born in Moscow in 1954, he started his diplomatic career in his early 20s after graduating from the Moscow State Institute of International Relations and the country’s diplomatic academy.