The International Criminal Court on Friday warned warring parties in Ukraine that attacks on civilians are a crime as invading Russian forces ramp up bombardments of city infrastructure.
"If attacks are intentionally directed against the civilian population: that is a crime. If attacks are intentionally directed against civilian objects: that is a crime," ICC chief prosecutor Karim Khan said.
"I strongly urge parties to the conflict to avoid the use of heavy explosive weapons in populated areas," added Briton Khan.
"There is no legal justification, there is no excuse, for attacks which are indiscriminate, or which are disproportionate in their effects on the civilian population.
"I am closely following the deeply troubling developments in hostilities. The events of recent days require me to again emphasise that all those involved in this conflict must adhere strictly to the applicable rules of international humanitarian law."
The conflict Wednesday saw a maternity ward and a hospital hit in the surrounded southeastern city of Mariupol where a young girl was one of three people listed as killed in an attack which brought widespread condemnation.
The Hague-based ICC last week opened an investigation into the situation in Ukraine after 39 member states gave it the green light to do so.
Khan said Friday Japan and the Republic of North Macedonia had also called for the investigation.
Ukraine is not a signatory to the Rome Statute treaty which established the ICC but it did in 2014 officially recognise the court's jurisdiction for crimes committed on its soil.
Russia withdrew its signature from the Rome Statute in 2016.
