Poland is considering a proposal from Kiev to shoot down Russian missiles headed for Polish territory while they are still in Ukrainian airspace.

The proposal was included in a security cooperation agreement signed by Ukrainian President Volodymyr Zelenskyy and Polish Prime Minister Donald Tusk in Warsaw this week.

Zelensky said he was "convinced" the deal could be implemented quickly, although Poland will consult with NATO before attempting to shoot down any Russian missiles.

"At this stage, this is an idea. What our agreement said is that we will consider this idea," Polish Foreign Minister Radoslav Sikorski told the American Enterprise Institute in Washington today.

Sikorski confirmed that Russian missiles fired from the St Petersburg area towards Ukrainian targets had previously entered Polish airspace for about 40 seconds before returning to their targets. The proposal would cover any rocket that crosses western Ukraine towards Poland.

"Our dilemma is as follows. If we shoot them down only when they enter our airspace, the debris is a threat to our citizens and our property. And the Ukrainians are saying, 'Please, it won't stop us from doing it in our airspace when they are in imminent danger of crossing into Polish territory.' In my opinion, this is self-defense, but we are exploring the idea," said Sikorski. /SkyNews