US President Joe Biden has called his Russian counterpart Vladimir Putin a "worthy adversary."

Asked about his upcoming meeting with Putin at the post-NATO summit news conference, Biden did not specify what results he expected, saying only that they will discuss areas where they can work together, but if Russia refused to work together on matters such as cybersecurity is, they will respond the same way.

"He's bright, he's tough, and I've found that he is—as they say when I used to play ball—a worthy adversary," Biden said of Putin, and expressed hope that the Russian president will show interest in changing the way he is perceived in the world.

The meeting of the two leaders will take place Wednesday in Geneva, Switzerland.