William J. Burns, the director of the Central Intelligence Agency, met his Russian counterpart in Turkey on Monday to warn Russia against the use of nuclear weapons in Ukraine, a White House spokesman said.

The National Security Council said Burns’s meeting with Sergei Naryshkin, head of Russia’s SVR foreign intelligence service, in Ankara was not in any way meant to negotiate or discuss any settlement of the war in Ukraine.

Kyiv was briefed in advance on the trip, the spokesman said. President Joe Biden has insisted that Ukraine, and not the US, will dictate if and when negotiations commence to end the war.

Burns was also set to raise the case of Americans detained in Russia, the National Security Council said.

Dmitri S. Peskov, the Kremlin’s spokesman, would not confirm or deny whether the meeting took place. A CIA spokeswoman declined to comment. The agency never comments on the director’s travel.

Burns, a former US ambassador to Russia who was sent to Moscow in late 2021 by Biden to caution Putin about the troop build-up around Ukraine, is not discussing a potential settlement to the war in Ukraine, the spokesperson said.

“We briefed Ukraine in advance on his trip. We firmly stick to our fundamental principle: nothing about Ukraine without Ukraine.”

Putin has repeatedly said Russia will defend its territory with all available means, including nuclear weapons, if attacked.

Putin says the West has engaged in nuclear blackmail against Russia.

The remarks raised particular concern in the West after Moscow declared in September that it had annexed four Ukrainian regions that its forces control parts of.

The US-Russian contact in Turkey was first reported by Russia’s Kommersant newspaper. The Kremlin, asked about the Kommersant report, said it could neither confirm nor deny it.

The SVR did not respond to a request for comment.

Beyond the war, Russia and the US have a host of outstanding issues to discuss, ranging from the extension of a key nuclear arms reduction treaty and a Black Sea grain deal to a possible U.S.-Russian prisoner swap and the Syrian civil war.

UN Secretary-General Antonio Guterres asked at a summit of the G20 leading economies in Indonesia about the US.-Russian contact inTurkey, saying the UN was not involved.

“It’s very positive that the US and Russia are having talks because that is an extremely relevant development in relation to the future, but we are not involved,” Guterres said.

Biden said this month he hoped Putin would be willing to discuss seriously a possible prisoner swap to secure the release of US basketball star Brittney Griner, who was sentenced to nine years in a Russian penal colony on drugs charges.

Former US Marine PaulWhelan, who holds American, British, Canadian and Irish passports, was sentenced in 2020 to 16 years in a Russian jail after being convicted of spying. He denied the charge.

Viktor Bout, a Russian arms dealer jailed in the US, has been mentioned as a person who could be swapped for Griner and Whelan in any future prisoner exchange.

New York Times News Service and Reuters