Russia’s ambassador to Turkey was killed Monday after gunfire erupted at a photo exhibit in the Turkish capital where he was one of the speakers, Russian officials said. One gunman also was killed in the apparent targeted attack.

There was no immediate claim of responsibility for the attack. But video posted on social media purported to show a Turkish-speaking decrying violence in Syria, where Russia is a key backer of Syrian President Bashar al-Assad.

Russia’s Foreign Ministry spokeswoman, Maria Zakharova, said Ambassador Andrei Karlov died after being hit in the back by gunfire at the event in Ankara. Earlier, Russia’s Foreign Ministry said Karlov has been hit by one gunshot, but efforts to treat him were delayed by further gunfire.

Several other people were wounded in the gallery attack, but their identities were not immediately made public. Officials in Moscow confirmed that one gunman was killed. It was not known if there were other attackers.

Russia and Turkey, a foe of Assad, recently joined to broker a deal to evacuate civilians and rebel fighters from the last opposition enclaves in Aleppo, a major Syrian city that has been under relentless attacks from Syrian forces and their allies.

“Allah Akbar! Do not forget Aleppo!” said the gunman, according to the widely circulated video. “Do not forget Syria! Do not forget Aleppo! Do not forget Syria! As long as our lands are not safe, you will not be safe!

The authenticity of the video could not be independently confirmed.

CNN Turk television reported that shooting continued after the attack targeting the ambassador.

The Associated Press published a photo showing a man lying on the ground with an armed assailant dressed in a suit standing nearby.

Karlov started his diplomatic career during the Soviet era in 1976 and had previously served at Russian embassies in Seoul and Pyongyang, North Korea. He took the post in Ankara in July 2013, according to the embassy’s website.

Turkey has been hit by a serious of attacks in recent years blamed on groups including the Islamic State and Kurdish separatists, who have battled the government for decades for greater autonomy in Turkey’s southeastern regions.

In Washington, State Department spokesman John Kirby condemned Monday’s attack.