Putin and Andrei Karlov,
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Frants Klintsevich claimed a NATO state's secret service could be behind today's attack
The secret services of a NATO country is "highly likely" to have been behind today's assassination of the Russian ambassador to Turkey, an ally of Vladimir Putin has claimed.

Senator Frants Klintsevich said the cold-blooded killing of Andrei Karlov, who died after being shot five times in the back, was a "planned action".

He continued: "Everyone knew that he was going to attend this photo exhibition.

"It can be ISIS, or the Kurdish army which tries to hurt Erdogan.

"But may be - and it is highly likely - that representatives of foreign NATO secret services are behind it."

Mevlüt Mert Altıntaş
The Russian ambassador to Turkey was killed in cold-blood this afternoon
He said regardless of the true identity of the perpetrators, Russia now faced a huge "challenge".

Mr Klintsvich concluded: "What has happened is a true provocation, a challenge. It is a challenge for Russia."

gunman
The gunman was killed following the bloody attack in Ankara
NATO has condemned the killing, which took place this afternoon in an Ankara art gallery.

Secretary General Jens Stoltenberg said: "I condemn the killing of Russia's ambassador to Turkey. My condolences to his family and Russian people. No justification for such a heinous act."

The gunman in today's attack has been identified as a 22-year-old police officer Mevlüt Mert Altıntaş.

He was standing behind Mr Karlov during his speech before opening fire and shouting "Allahu Akbar".

A source said the 22-year-old off-duty riot police officer introduced himself as ambassador's personal security detail before opening fire after screaming "you Russians destroyed Aleppo and Syria".

gunman
Frants Klintsevich said it was "highly likely" a NATO state's secret service could be responsible
One witness, who did not wish to be named, said: "He took out his gun and shot the ambassador from behind. We saw him lying on the floor and then we ran out."

Shocking video taken in the aftermath of the attack shows the gunman bellowing about Aleppo and pointing the revolver into the crowd, who scream and flee.