"I am sure that this will not increase the security of Ukraine itself, and in general will make the world much more vulnerable and lead to additional tension in the international arena," Putin said.

Preventing Kyiv from joining the alliance was one reason President Vladimir Putin gave for launching the military operation in Ukraine.

Putin spoke to journalists a day after a summit in Lithuania in which NATO pledged its backing for Kyiv but failed to offer it a timeline for membership.

Kyiv has been asking for more advanced and long-range weapons, including missiles, to push back Russian forces.

Long-range missiles "cause damage but nothing critical is happening in the combat zones where they have been used. The same goes for foreign-made tanks," Putin told journalists.

"The delivery of new weapons will only aggravate the situation, aggravate it for the Ukrainian side and will fuel the conflict," he said.