Speaking on the sidelines of the climate change summit in Paris on Monday, Russian President Vladimir Putin declared that Moscow had grounds to suspect that Turkey shot down the Russian Su-24 warplane on Nov. 24 to secure illegal oil deliveries from Syria to Turkey, according to The Independent.

"At the moment we have received additional information confirming that that oil from the deposits controlled by Islamic State militants enters Turkish territory on industrial scale," Putin said.

"We have every reason to believe that the decision to down our plane was guided by a desire to ensure security of this oil's delivery routes to ports where they are shipped in tankers," he added.

Speaking at the same conference, Turkish President Recep Erdogan strongly denied the accusations, even stating that he is willing to step down if Putin's allegations are proven right, reports RT News.

"We are not that dishonest as to buy oil from terrorists. If it is proven that we have, in fact, done so, I will leave office. If there is any evidence, let them present it, we'll consider," he said, further stating that countries from which Turkey acquires oil are "well-known."

Turkish Prime Minister Ahmet Davutoglu has also condemned Russia's stance on the issue, stating that Ankara will not apologize over the incident. The prime minister also said that by shooting down the Russian plane, the country was only "doing its duty."

"No country should ask us to apologize. The protection of our land borders, our airspace, is not only a right, it is a duty. We apologize for committing mistakes, not for doing our duty," he said.

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