US President Joe Biden joins fellow Western leaders in Brussels on Thursday for three summits on Russia’s war in Ukraine, a month after the invasion began.
One issue that will inevitably come up for discussion is the level of Europe’s willingness to engage militarily in the conflict.
Nato leaders have already sent thousands more troops to the alliance’s eastern flank, along with more air defence batteries, warships and aircraft in a bid to boost its own defences.
But not all have been willing to supply weapons.
The alliance has also made it clear it won’t become more directly involved and Zelensky’s repeated requests for a no-fly zone over Ukraine has been ruled out.
Nato has also yet to decide how it would respond if Russia were to dramatically escalate the conflict in Ukraine – such as the attack on a Western weapons convoy, and the use of chemical, or even tactical nuclear weapons.