Pentagon: This is between Turkey and Russia, and 'our focus is on ISIS'

US operations in Syria and Iraq are continuing "as planned," Army Colonel Steve Warren said Tuesday, hours after Turkey reportedly shot down a Russian warplane.

"This is an incident between the Russian and the Turkish governments. It is not an issue that involves the combined joint task force or Operation Inherent Resolve," Warren said at a Pentagon briefing from Baghdad, using the name for the US military operation against the Islamic State (also known as ISIS or ISIL).

"Our combat operations against ISIL continue as planned and we are striking in both Iraq and Syria," added Warren, a spokesman for the US-led military campaign against the group.

Warren later reaffirmed that the US was not involved in the downing of the plane.

"This is Turkey and Russia. This is their incident," he said. "Our focus is on ISIL. The US military's feeling is our mission is to fight ISIL in Syria and Iraq. … That's what we're focusing on."

He clarified that forces the US has trained and partnered with in Syria were not in the area where the Russian plane was downed.

Warren also called out Russia for hitting moderate rebels in Syria under the guise of fighting ISIS in the country. Some experts have said that Russia's main goal in Syria is to prop up the regime of President Bashar al-Assad, who has killed thousands of civilians as he struggles to maintain power amid a four-year-long civil war.

"A majority of [Russia's] strikes have been strikes that are a direct benefit to the Assad regime, and it's the Assad regime that's the problem here … and has brought suffering and misery to the Syrian people and has led to the growth of ISIL itself," Warren said.

"We've seen the Russians already strike forces that are moderate Syrian opposition forces. We've seen them do this and it flies directly in the face of what they said they would do," he added.

Experts argue that Assad's atrocities help ISIS recruit. Showing the violence of the regime can help radicalize people while also convincing them that they need ISIS for protection from the regime.

In comments following the Russian plane downing, President Vladimir Putin affirmed his claims that Russia is fighting ISIS in Syria and said that Turkey downing its jet was "linked to a stab in the back delivered to us by accomplices of terrorists."

"We established a long time ago that large quantities of oil and oil products from territory captured by Islamic State have been arriving on Turkish territory," he continued, saying that was how ISIS had been funding itself.

"And now we get stabbed in our back and our planes, which are fighting terrorism, are struck. This despite the fact that we signed an agreement with our American partners to warn each other about air-to-air incidents and Turkey ... announced it was allegedly fighting against terrorism as part of the US coalition."