Erdogan's comments came as NATO leaders huddled in Washington and Kremlin spokesman Dmitry Peskov said Russia was planning "response measures" to contain the "very serious threat" from the alliance.

"The possibility of a direct conflict between NATO and Russia is undoubtedly worrying," said Erdogan, who is in Washington for the NATO summit. "Any steps that could lead to this outcome should be consciously avoided."

Erdogan spoke a day after NATO allies announced they had started transferring F-16 jets to Ukraine while stepping up promises to Kyiv on eventual membership in the alliance, at a 75th anniversary summit clouded by political uncertainties in the United States.

On the eve of the summit, Russia fired a barrage of missiles at Ukraine, killing dozens, including in Kyiv where a children's hospital was heavily damaged.

Peskov, in comments published by Russian news agencies, said the Western military alliance was now "fully involved in the conflict over Ukraine".

NATO member Turkey has sought to balance ties between its two Black Sea neighbours Russia and Ukraine since Moscow's full-scale invasion in 2022.

Ankara has sent drones to Ukraine while shying away from Western-led sanctions on Moscow.

Last year, Erdogan, whose government is seeking to mediate a peace deal between Russia and Ukraine, said Ukraine "undoubtedly" deserved NATO membership when he met President Volodymyr Zelensky.

-'Deeper conflicts'-

On Thursday, Erdogan also played down the influence of the Shanghai Cooperation Organisation (SCO), a regional bloc that Moscow and Beijing have promoted as a counterweight to US domination.

"We do not think that the Shanghai Cooperation Organisation is an alternative to NATO," Erdogan said.

Turkey has been an SCO dialogue partner since 2012 and Erdogan, who attended the July summit, has suggested in the past he wanted full membership.

Before flying to Washington on Tuesday, Erdogan called for more NATO involvement in the war between Israel and the Palestinian militant group Hamas.

Erdogan has already voiced concerns over what he said were Israeli plans to attack Lebanon and on Thursday renewed his warnings about the war spreading.

"Israel's threats and attempts to spread the conflict must come to an end," he said.

"Otherwise, our region will face the risk of deeper conflicts and even a war."