Zelensky has vowed to return home the Ukrainians held in captivity by the pro-Russian forces in Donbass.
The comedian's uncoventional campaign has barely mentioned Ukraine's long-standing conflict with Russia, and has instead focused on fighting corruption.
Poroshenko has also appealed personally to German leader Angela Merkel reminding of her role in striking the Minsk II Agreement
The incident has caused international fears that the war in Ukraine simmering since 2014 may escalate.
The number of Ukrainians who have traveled to the EU since Ukraine was granted a visa-free regime by the Union
The European Union and Ukraine are set to hold their 20th annual summit in Brussels amid recognition that the latter