Turkey's prime minister struck a defiant tone Friday in his nation's growing spat with Russia, declaring that his country cannot be "brought to its knees" by Russian economic sanctions imposed in response to Turkey's downing of a Russian warplane.

In a speech during a visit to Baku, Azerbaijan, Prime Minister Ahmet Davutoglu again defended Turkey's action and said Turkey won't apologize for defending its borders.

Davutoglu insisted Turkey did not know the nationality of the plane it downed inside Turkish air space. He suggested for the first time, however, that the plane was brought down because Turkey could not "morally" allow the plane to trespass on Turkish territory before bombing areas in Syria where ethnic Turkish populations live.

"No one can blame Turkey, no one can expect an apology from Turkey," Davutoglu said in the speech, which was televised on Turkish television. "We would not apologize for defending our borders."

"Those who believe that economic sanctions against an honorable nation like Turkey can bring it to its knees will be mistaken," Davutoglu said.

Turkey insists the plane violated its airspace despite repeated warnings. The shoot-down, the first time a NATO country has downed a Russian plane in more than half a century, sparked a bitter falling out between the two nations, which had developed robust economic ties.

Russia has retaliated by deploying long-range air defense missile systems to its base in Syria, 50 kilometers (30 miles) south of the border with Turkey. It also slammed an array of economic sanctions on Turkey, including a ban on imports of fruit and vegetables and the sales of tourism packages. Russia also scrapped talks with Turkey on building a pipeline to export Russian natural gas to Europe.

Moscow says its warplanes have been targeting terrorist groups near Syria's border with Turkey, while Ankara says the Russian airstrikes have been aimed at moderate militant groups made of ethnic Turks who oppose Syrian President Bashar Assad's regime. The militants shot and killed the downed plane's pilot while he was descending on parachute and also killed a Russian marine involved in rescuing the plane's co-pilot.

"Neither our conscience, nor our history, nor our morals could have allowed (the plane) to bomb innocent people by violating (our border)," Davutoglu said.

Russian President Vladimir Putin on Thursday accused Turkey of a "treacherous war crime" and has vowed to make Turkey "feel sorry" for its actions.

Davutoglu said the sanctions would be detrimental to both sides. He again urged Russia to be open to dialogue so the two countries which had enjoyed warm ties until last week's incident can resolve the issue diplomatically.