A spokesperson for Russia's Foreign Ministry, meanwhile, rejected any suggestion that Moscow had opposed or was hindering efforts to introduce a ceasefire.
Both were speaking on Wednesday hours before a three-day ceasefire proposed by Russia was to go into effect to mark the anniversary of the victory over Nazi Germany in World War II.
"Ukraine's proposal to cease strikes and establish at least a 30-day ceasefire remains in force," Zelenskiy said in his nightly video address.
"We are not withdrawing this proposal, which could give diplomacy a chance."
Zelenskiy also appeared to acknowledge the numerous drone attacks that have been targeting Russian sites, including the city of Moscow, as the World War II commemorations approached.
"It is absolutely fair that Russian skies, the skies of the aggressor, are also not calm today, in a mirror-like way," he said.
Russia, he said, had made no response to the 30-day offer "except for new strikes. This clearly and obviously demonstrates to everyone who the source of the war is".
The US proposed the 30-day ceasefire in March and Ukraine agreed. Russia has said such a measure could only be introduced after mechanisms to enforce and uphold it are put in place.
Russian Foreign Ministry spokeswoman Maria Zakharova said Russia had observed a separate 30-day moratorium on attacks on energy sites and had also observed a ceasefire to coincide with the observance of Orthodox Easter in April.
"The only obstacle to the ceasefire is Kyiv, which violates agreements and is unwilling to seriously discuss the terms of a long-term ceasefire," Zakharova said in response to comments by US envoy Keith Kellogg.
"Russia has never been opposed to a ceasefire. All the more so, we have done this twice," Zakharova said in a comment posted on the Foreign Ministry's website.
"Having Kyiv observe them could have been a step towards a long-term ceasefire. Unfortunately, Kyiv sabotaged both. The Ukrainian military violated the moratorium 135 times and the Easter ceasefire nearly 5000 times."
