ANKARA (AFP) - President Recep Tayyip Erdogan denied on Thursday that Turkey bought any oil from the Islamic State in Iraq and Syria (ISIS) group, insisting his country's fight against the militants was "undisputed".

"Shame on you. Those who claim we buy oil from Daesh (ISIS) are obliged to prove it. If not, you are a slanderer," Erdogan said, lashing out at Russian charges after the downing of a warplane on the Syrian border.

Tuesday's incident prompted a tough response from Moscow, a major trade partner and Turkey's largest energy supplier.

But Turkish Foreign Minister Mevlut Cavusoglu said Ankara did not need to apologise "on an occasion that we are right," adding that he had already said "sorry" in a phone call with Russian counterpart Sergei Lavrov.

Russian President Vladimir Putin has denounced the act as a "stab in the back" by "accomplices of terrorists."

But Erdogan denied Ankara was collaborating with ISIS.

"Our country's stance against Daesh has been clear since the very beginning," Erdogan said in a speech to local officials at his presidential palace in the Turkish capital.

"There is no question mark here. Nobody has the right to dispute our country's fight against Daesh or to incriminate us."

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Turkey and Russia stand on opposing sides of the four-year Syrian conflict, with Ankara pushing for the ouster of President Bashar al-Assad by backing moderate opposition rebels.

Moscow is one of the few remaining allies of the Damascus regime.

Russia further enraged Turkey with the launch of its air campaign in Syria in September, accusing Moscow of focusing its fire on moderate rebels rather than ISIS militants.

"Those who carry out a military campaign with the pretext of fighting Daesh are targeting anti-regime opponents," Erdogan said.

"You say you are fighting Daesh. Excuse me, but you are not fighting Daesh. You are killing our Turkmen kinsmen hand-in-hand with the regime in order to clear areas north of Latakia," he said, referring to the Syrian port city.

ISIS extremists have severely damaged Islam and the Muslims, he said, but added there was no difference between "an organisation's terror and state terror," referring to the Assad regime.

Erdogan called Russia a "strategic partner" which he said required solidarity rather threats. "We are saddened by this," he said.

"There is no reason for us to target Russia with which we have multi-faceted and very strong ties, without any border violation," he noted, saying that disagreements with Moscow over the Syrian crisis and Ankara's activating its military rules of engagement were two separate things.

"If the same incursion happens today, Turkey will be obliged to retaliate."

Erdogan also hit back at Putin's charges that Turkey's leaders were encouraging the Islamisation of the country.

"How dare you speak like that," said Erdogan. "Ninety-nine per cent of Turkey is Muslim."