Stubb made the statement in an interview with CNBC.
The Finnish president said he had recently discussed nuclear security with China’s foreign minister.
“Two days ago, I hosted the Chinese foreign minister for dinner in Finland, and we discussed the nuclear issue,” Stubb said.
“The Chinese are very categorical: no, this will not happen.”
At the same time, Stubb said the possibility of escalation should not be underestimated.
“It is very important that we are able to contain this situation, but there is a risk of escalation, and we have to take it seriously,” he added.
Ukrainian President Volodymyr Zelenskyy also said earlier that several European leaders told him during the NATO summit in Ankara about China’s firm position on the possible use of nuclear weapons by Russia.
Beijing made clear to the Kremlin in an ultimatum-like manner for the first time that the use of nuclear weapons was unacceptable, Zelenskyy said.
China had earlier rejected Russian claims that France and the United Kingdom had allegedly transferred nuclear weapons to Ukraine, stressing that it opposes the use of nuclear weapons under any circumstances.