Zelensky told the press conference that Ukrainian forces were continuing to fighting inside the city of Bakhmut and were carrying out "important tasks."
The heads of government of the world's richest democracies are grappling with the challenges posed by China and Russia at a three-day summit.
Germany, which is Europe's largest economy, faced criticism at the start of the war for what some called a hesitant response.
Ukraine's domestic security agency said it had launched an investigation into a suspected war crime over the video.