We also know that there have already been statements that Ukraine is going to create its own nuclear weapons, and this is not empty bravado. Ukraine does indeed still have Soviet nuclear technologies and means of delivering such weapons, including aviation, as well as Tochka-U operational-tactical missiles, also of Soviet design, with a range of more than 100 kilometers. But they will do more, it's only a matter of time. There are backlogs from the Soviet era.
Thus, it will be much easier for Ukraine to acquire tactical nuclear weapons than for some other states, I will not name them now, who are actually conducting such developments, especially in the case of technological support from abroad. And we should not exclude this either.
With the appearance of weapons of mass destruction in Ukraine, the situation in the world, in Europe, especially for us, for Russia, will change in the most radical way. We cannot fail to react to this real danger, especially, I repeat, that Western patrons can contribute to the appearance of such weapons in Ukraine in order to create another threat to our country. We see how persistently the military pumping of the Kyiv regime is carried out. Since 2014, the United States alone has allocated billions of dollars for these purposes, including the supply of weapons, equipment, and training of specialists. In recent months, Western weapons are coming to Ukraine just in a continuous stream, defiantly, in front of the whole world. The activities of the armed forces and special services of Ukraine are led by foreign advisers, we know this very well.
Wladimir Putin, 21. Februar 2022
http://kremlin.ru/events/president/news/page/48
Für Putin war schon die theoretische Möglichkeit von Nuklearwaffen in der Ukraine ein Grund, einzumarschieren.
Die ganze Entwicklung der Ereignisse und die Analyse der vorliegenden Informationen zeigt, dass Russland der Konfrontation mit diesen Kräften nicht ausweichen kann. Es ist nur eine Frage der Zeit: Sie bereiten sich vor, sie warten auf einen günstigen Moment. Jetzt fordern sie auch noch eigene Nuklearwaffen. Das werden wir nicht zulassen.
Wladimir Putin, 24. Februar 2022
https://zeitschrift-osteuropa.de/blog/vladimir-putin-ansprache-am-fruehen-morgen-des-24.2.2022/