"Packages were moving along the belt, and a colleague was taking them off, and at that moment the explosion occurred," a man named Mykola said in a video published by the news outlet.
"It seemed to me it looked like a Shahed [drone] strike, with sparks coming from above. The blast caused a fire."
The workers initially tried to move the remaining packages but were forced to evacuate due to heavy smoke.
On the morning of June 5, an explosion occurred during the inspection of a package at a postal sorting center in Kyiv, killing a 59-year-old man and injuring two others, aged 37 and 41.
Law enforcement officers are investigating all the circumstances and causes of the blast.
The prosecutor's office has classified the explosion as a terrorist act. A criminal case has been opened under Part 3 of Article 258 of the Criminal Code of Ukraine.