The United Nations says members of the Daesh Takfiri terrorist group have fatally shot children trying to flee heavy exchanges of gunfire between the extremists and government forces in the western part of Mosul, condemning the crime as “despicable.”

“Shooting children as they try to run to safety with their families – there are no words of condemnation strong enough for such despicable acts,” said Zeid Ra’ad al-Hussein, the UN high commissioner for human rights, on Thursday.

The Office of the United Nations High Commissioner for Human Rights (OHCHR) also said in a statement that there had been a “significant escalation” of civilian deaths by Daesh, which has been targeting those trying to flee Mosul.

“Credible reports indicate that more than 231 civilians attempting to flee western Mosul have been killed since May 26, including at least 204 over three days last week alone,” the OHCHR said.

The UN human rights office added that dozens of people were shot dead by Daesh terrorists in Mosul’s al-Shifa neighborhood on May 26, June 1 and June 3.

The agency also said that it had launched an investigation into reports that between 50 and 80 people lost their lives in an aerial attack on the Zanjili district of western Mosul on May 31. It did not, however, provide any information as to who had carried out the strike.

The OHCHR noted that the deaths in Zanjili were reportedly caused by one of several recent airstrikes that had inflicted civilian casualties, adding that the UN agency is seeking further information about those attacks.

The UN high commissioner for human rights called on Iraqi authorities “to ensure that those who are responsible for these horrors are held accountable and brought to justice in line with international human rights laws and standards.” Hussein stressed that “the victims of such terrible crimes must not be forgotten.”

On Monday, Peter Hawkins, representative of the United Nations International Children’s Fund (UNICEF) in Iraq, estimated that 100,000 girls and boys are still living under extremely dangerous conditions in Mosul’s militant-held Old City neighborhood and other districts.

The UN agency is receiving “alarming reports” of civilians being killed, including children, in the city’s western half, he added.

The UNICEF representative, however, didn’t give a specific number of children killed in the crossfire.

Iraqi army soldiers and volunteer fighters from the Popular Mobilization Units, commonly known by the Arabic name Hashd al-Sha’abi, have made sweeping gains against the Takfiri elements since launching the Mosul operation on October 17, 2016.

The Iraqi forces took control of eastern Mosul in January after 100 days of fighting, and launched the battle in the west on February 19.

Jens Laerka, the spokesperson of the Office for the Coordination of Humanitarian Affairs, said on May 30 that nearly 600,000 civilians have been displaced until then amid the operation to drive Daesh terrorists out of western Mosul.

He added that there were still major humanitarian concerns regarding the protection of 180,000 people, who are still besieged inside Mosul’s Old City and other districts north of the city.