Turkey shot down a Russian warplane near the Turkish-Syrian border. Turkey said it hit the plane after it violated Turkey’s airspace and ignored 10 warnings, reported CNN.

One of the two pilots was killed in the air by fire from the ground, according to Russia’s state-run news agency RIA Novosti. The fate of the second pilot wasn’t disclosed.

Meanwhile, a Russian marine was killed on Tuesday during an operation to rescue the two pilots, who were flying a Su-24 warplane in a combat sortie, claimed RIA Novosti.

According to NYT, it was thought to be the first time a NATO country has shot down a Russian plane in a half-century. And while few expect a military escalation, with neither Russia nor NATO wanting to go to war, the incident highlighted the dangers of Russian and NATO combat aircraft operating in the same theater and has soured chances for a diplomatic breakthrough over Syria.

The Russian plane was dealt with because it “did not answer our warning,” Turkish President Recep Tayyip Erdogan said on Tuesday.

ISIS isn’t present at that border area, but Turkmen were there, Erdogan said. Anyone who bombs that area attacks “our brothers and sisters — Turkmen,” Erdogan said in Ankara.

Erdogan said the plane incident was not something Turkey wanted to see happen, and “this does not indicate any animosity” toward any country.

He added the downed jet was “one of two” planes but didn’t elaborate beyond that.

It’s been Turkey’s cool approach that has prevented similar incidents up to now, he added.

Turkey’s ambassador to the United States, Serdar Kilic, tweeted: “Understand this: Turkey is a country whose warnings should be taken seriously and listened to. Don’t test Turkey’s patience. Try to win its friendship.”

However, President Vladimir Putin of Russia denied the plane had been in Turkish air space and made clear he would not let the matter drop, with the risk of an international escalation.

“Today’s loss was a stab in the back by the accomplices of terrorists,” he said. “Our pilots and our aircraft never threatened the territory of Turkey. That much is obvious.”

He insisted that the Russian air force had been taking part in operations against the Islamic State of Iraq and the Levant (ISIL). “We will never tolerate such crimes like the one committed today,” he said.

“If ISIL has such money, and we’re talking about tens, hundreds of millions, possibly billions of dollars from oil revenues, plus protection from the armed forces of an entire country, then it is understandable why they are so audacious, so blatant, why they murder people in the most horrendous ways, whey they carry out terrorist attacks across the world including in the heart of Europe,” he said.

The Telegraph said, Britain Prime Minister David Cameron, spoke to his Turkish opposite number Ahmet Davutoglu and urged him to maintain lines of communication with Russia, his spokeswoman said.

Mr. Cameron is keen to press ahead with airstrikes on ISIL in Syria, something that would be made more dangerous if the confrontation between Turkey and Russia escalated further.

“It doesn’t change two important factors, which are the threat posed by ISIL to the UK and the need to work in a coalition to be doing more,” his spokeswoman said. “The Prime Minister has said he believes in doing more – in Syria.”

[ ALSO READ: David Cameron Wants UK to Strike ISIS ]