NATO is on high alert for Russian missiles that fell in Poland, killing two, after a rain of more than 100 rockets exploded in Ukraine this afternoon, in Vladimir Putin's latest challenge to the world as the G20 summit was held. It is the first time that an Alliance country has been hit directly in the conflict.
Polish government spokesman Piotr Muller has just given a press conference in the capital Warsaw. He said that the government is increasing the readiness level of the army. This in response to the explosion near its border with Ukraine. Muller confirmed that 2 people were killed in the incident. He told reporters that the government was considering whether to activate Article 4 of the NATO Treaty. This would mean holding a meeting of NATO members as their "territorial integrity, political independence or security" was threatened.

There are many concerns that the missile explosion in Poland may constitute a violation of NATO Article 5. This is if it is established that the cause of the death of 2 people was a Russian attack. In Article 5, NATO's founding treaty focuses on collective defense. So, if one of the member states is attacked, the rest come to its defense and the Alliance acts as a whole. Article 5 was adopted at a time when the bloc was under threat of attack from the former Soviet Union.
"Collective defense means that an attack against one ally is considered an attack against all allies," this article states.
Article 5 has only been activated once by NATO since it was signed in 1949. This happened the day after the September 11, 2001 terrorist attacks on the World Trade Center and Pentagon buildings in the US.
So far, Poland has stated that it is considering activating NATO's Article 4, which stipulates that the parties will consult together and decide whether their territorial integrity, political independence or security is under threat.