The US and its allies have killed between 800 and 900 ISIS fighters in the operation to retake Mosul, US Army Gen. Joseph Votel said Thursday. US military officials estimate that there are 3,000 to 5,000 ISIS fighters defending the last major stronghold of the terror group in Iraq, and an additional 1,500 to 2,000 ISIS soldiers in a zone outside the city. Votel is the head of US Central Command and is assisting the Iraqis in the fight for Mosul. A coalition of about 100,000 forces began the operation 10 days ago, and have been slowly gaining ground toward the city, liberating villages from ISIS rule along the way. Clashes with ISIS fighters are expected to intensify the closer in troops get, and in Mosul itself bloody street-to-street skirmishes are expected, CNN has reported. ISIS is now sending “suicide squads” to Mosul from its symbolic capital of Raqqa in Syria, which the US and coalition forces also plan to try to capture soon. ISIS executed a total of 232 people near Mosul on Wednesday, United Nations Human Rights spokesperson Ravina Shamdasani told CNN on Friday. The UN Human Rights Office also said that since October 17, ISIS has been “taking tens of thousands of men, women and children from the outskirts of Mosul and bringing them into the city … to use them as human shields against the Iraqi forces advance on Mosul.” The Mosul offensive has attracted attention on the presidential campaign trail, with Republican nominee Donald Trump repeatedly attacking the Pentagon for publicly discussing the operation before it started. He repeated the charge again in an interview aired on Thursday. “I’ve been hearing about Mosul now for three months,” Trump told ABC’s George Stephanopoulos. “‘We’re going to attack. We’re going to attack.’ Meaning Iraq’s going to attack but with us, OK? We’re going to attack. Why do they have to talk about it?” Trump also criticized former Army War College dean Jeff McCausland after the military expert said the candidate lacks a firm grasp of military strategy. “You can tell your military expert that I’ll sit down, and I’ll teach him a couple of things,” Trump said.