A man carries his daughter on his back after fleeing their home due to fighting between the Iraqi forces and Islamic State militants in Mosul's al-Zanjili's district in Iraq. Erik De Castro/REUTERS

A U.N. report Thursday outlines that the Islamic State Group, also known as ISIS, has killed at least 231 people in Mosul, Iraq in the past two weeks. Many of the civilians were killed while trying to leave the city.

The increased casualties in the city marks an uptick in violence which includes using civilians as human shields.

Read: ISIS In Iraq: Mosul Overwhelmed With PTSD After Years of Islamic State Rule

On June 1 alone, ISIS killed one-hundred and sixty-three people including women and children near a Pepsi factory. The people killed were attempting to flee the al-Shifa neighborhood in western Mosul because of clashes between ISIS and Iraqi Security Forces. On Sunday, ISIS killed forty-one in the same neighborhood.

On May 26, ISIS killed twenty-seven people including fourteen women and five children again in the al-Shifa neighborhood.

“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 UN High Commissioner for Human Rights Zeid Ra’ad Al Hussein in a statement. “I call on the 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. The victims of such terrible crimes must not be forgotten.”

The U.N. also reports that it is investigating civilian casualties caused by Iraqi and coalition airstrikes. The U.N. said preliminary reports indicate that as many as eighty people were killed in a May 31 strike in Zanjilly, an ISIS-held neighborhood in western Mosul.

The U.N. has urged that Iraqi and coalition forces use an abundance of caution because of the amount of civilians that have been killed in the conflict.

Thousands of Iraqi forces have been sent to take the city back from ISIS and according to the BBC, more than 580,000 people have fled the city since the operation to take it back beginning in October 2016.

In recent months Iraqi Security Forces have been gaining territory in the city, causing the more brutal violence from ISIS, including the use of human shields and sniper fire.

“(ISIS)’s strategy of using children, men and women to shield themselves from attack is cowardly and disgraceful. It breaches the most basic standards of human dignity and morality. Under international humanitarian law, the use of human shields amounts to a war crime,” said Hussein in a March statement.

Read: ISIS In Iraq Hangs Civilian Bodies From Electrical Poles In Mosul Fight

The International Organization for Migration has also been monitoring the situation. They also have condemned ISIS’s tactics.

“With (ISIS) using civilians as human shields, even forcing their way into homes where families have gathered for safety and firing mortars from rooftops of houses with civilians in the lower floors, an increase in the number of innocent people being killed has been reported,” said the organization to the U.N.