Russia fired hundreds of drones at Ukraine Wednesday, killing at least five people and destroying a postal terminal, Ukrainian officials said.
The attacks came a day after the Kremlin rejected a Ukrainian proposal for a temporary ceasefire over the Easter holiday.
Diplomatic efforts to end Russia's four-year invasion have stalled in recent months, in part because the United States has shifted its focus towards the war with Iran.
Zelensky said Wednesday he had had a "positive" call with US negotiators Steve Witkoff and Jared Kushner about reviving the peace process.
The two sides had agreed to "strengthen security guarantees", he added, without elaborating.
"Ukraine is doing everything it can to support efforts for peace," Zelensky said in his evening address.
Russia fired 339 drones at Ukraine overnight, and more than 360 drones during the day, according to the Ukrainian air force.
A Russian drone killed four people in the central Cherkasy region. An earlier drone strike on a car in Ukraine's frontline Kherson region killed a woman and badly wounded two other people, regional authorities said.
Ukraine's Nova Poshta mailing company published an image showing a warehouse in the western city of Lutsk in flames following a Russian attack, thick smoke pouring from its roof.
Russia meanwhile stepped up pressure on the front line, claiming Wednesday to have taken two villages in eastern Ukraine and fully captured the Lugansk region, which its forces had already largely occupied.
Zelensky described the situation on the front as "quite tense" in an earlier social media post.
