The International Criminal Court (ICC) will be opening an investigation “as rapidly as possible” into potential war crimes and crimes against humanity committed by Russia before and during its invasion of Ukraine, according to ICC chief prosecutor Karim Khan.

Citing previous investigations from the ICC into alleged crimes committed by Russia before the invasion, Khan said “there is a reasonable basis to believe that both alleged war crimes and crimes against humanity have been committed in Ukraine in relation to the events already assessed during the preliminary examination by the Office.” He added that “given the expansion of the conflict in recent days, it is my intention that this investigation will also encompass any new alleged crimes falling within the jurisdiction of my office that are committed by any party to the conflict on any part of the territory of Ukraine.”

According to the Associated Press, the ICC “already has conducted a preliminary probe into crimes linked to the violent suppression of pro-European protests in Kyiv in 2013-2014 by a pro-Russian Ukrainian administration and allegations of crimes in Crimea, which Russia annexed in 2014, and eastern Ukraine, where Russia has backed rebels since 2014.”

In December 2020, then-ICC Prosecutor Fatou Bensouda said that the probe indicated “a broad range of conduct constituting war crimes and crimes against humanity within the jurisdiction of the Court have been committed” in Ukraine. At the time, however, the court’s prosecutors had not yet sought permission from judges to open a full-scale investigation into the alleged crimes.

The announcement comes amid reports that Russia has been killing civilians and using illegal cluster bombs and vacuum bombs during its invasion of Ukraine. According to U.N. human rights chief Michelle Bachelet, her office has confirmed that 102 civilians, including seven children, have been killed during the Russian invasion and 304 others wounded in Ukraine since Thursday. She warned that the true number was likely far more.