Ministers from Nato's member states are holding a second day of talks in Brussels to decide how best to continue to help Ukraine defend itself from Russia's invasion.
The North Atlantic Treaty Organization is a military alliance formed in 1949 by 12 countries, including the US and the UK. It was set up to counter the threat of post-war Russian expansion in Europe.
Members agree to come to one another's aid in the event of an armed attack against any individual member state.
Ukraine wants Nato countries - of which there are now 30 - to send troops to help fight Russia, but Ukraine is not a Nato member so there's no obligation for this to happen.
Nato has so far resisted Ukraine's calls to help in this way, as it fears doing so could lead to an all-out conflict between Russia and the West.
Nato members have helped Ukraine in other ways though - such as by sending weapons and money to fund Ukraine's armed forces.
Ukraine's foreign minister is joining the talks in Brussels to urge Nato to help Ukraine with the "three most important things" it needs to win the war - "weapons, weapons, and weapons".