ATLANTA — Ukrainian President Volodymyr Zelensky warned Western countries that the war will not stop at Ukraine -- and an attack on freedoms there will affect the rest of the world.

During an interview on ABC World News Tonight with David Muir on Monday, Zelensky again highlighted the need to secure Ukraine's airspace -- something he has urged the US and NATO to help do, to no avail.

"We cannot allow Russia to be active there only, because they're bombing us, they are shelling us, they are sending missiles, helicopters, jet fighters -- a lot of things," Zelensky said. "We don't control our sky."

He added that he believes US President Joe Biden "can do more" to stop the war. "I am sure he can and I would like to believe that. He is capable of doing that," Zelensky said.

The US stance: The US and NATO oppose creating a no-fly zone in Ukraine, warning that such a move could lead to "full-fledged war in Europe." Russian President Vladimir Putin said Saturday countries imposing such a no-fly zone would be considered to be participating in the conflict.

On Monday, the White House said Biden remains firm in his commitment to keep US troops out of the conflict.

Zelensky's response: The Ukrainian president said missiles were hitting civilian structures including universities and pediatric clinics. If a missile is flying overhead, "I think there is no other answer ... they need to be shot down. You have to preserve lives," he said.

And he warned the war would affect the rest of the world: "Everyone thinks that we are far away from America or Canada. No, we are in this zone of freedom. And when the limits of rights and freedoms are being violated and stepped on, then you have to protect us. Because we will come first. You will come second. Because the more this beast will eat, he wants more, more, and more." — CNN