MOSUL, Iraq 

Kurdish sources have accused the Islamic State of Iraq and the Levant, or Daesh -- also known as ISIL -- of destroying historic mosques in the northern Iraqi city of Mosul.

Hamo Kado, a mosque dating back to the Ottoman Empire period, was blown up by Daesh militants Thursday, according to Said Memozini, a Kurdistan Democratic Party representative.

Daesh was also accused of destroying another Mosul historical site at the ancient Assyrian city of Nimrud on Thursday in Mosul, Iraqi officials said.

UN Secretary-General Ban Ki-moon on Friday condemned the "systematic" destruction of Iraq's cultural treasures by Daesh militants and UNESCO’s Director General Irina Bokova called it a "war crime."

"This is yet another attack against the Iraqi people, reminding us that nothing is safe from the cultural cleansing underway in the country," Bokova said. "The deliberate destruction of cultural heritage constitutes a war crime." 

"I call on all political and religious leaders in the region to stand up and remind everyone that there is absolutely no political or religious justification for the destruction of humanity’s cultural heritage," Bokova added. 

In Washington, U.S. Secretary of State John Kerry said in a statement that he was "deeply disturbed" by reports that Daesh "extended its destruction of Iraq’s historical treasures to the ancient archeological site of Nimrud."

"These depraved acts are an assault on the heritage of the Iraqi and Syrian people by an organization with a bankrupt and toxic ideology," he said.

The purported incidents follow a video released by Daesh militants showing the extremist fighters destroying ancient artifacts in Mosul’s museum on Feb. 27. The monuments dated back to the 8th century B.C.

Iraq has plunged into a security vacuum since June 2014, when Daesh stormed the northern Iraqi province of Mosul and declared what it called a caliphate in Iraq and Syria.