The United States-led coalition against the Islamic State is currently helping the Iraqi Security Forces put together the force that will try to retake the city of Mosul, a spokesman said Friday.

Col. Steve Warren, the spokesman for Operation Inherent Resolve, made the announcement while addressing a news briefing in Washington. He was speaking via video link from Baghdad.

Warren told reporters it would still be “many months” before the Iraqi Security Forces began their campaign to recapture Mosul, which the Islamic State has occupied since June 2014.

“Right now our focus is ‘Let’s start training some brigades. Let’s start building some combat power. Let’s continue to train some police and start building up some combat power,’” he said.

Mosul is the capital of Nineveh province in northern Iraq and is one of the nation’s largest cities.

Warren told reporters the coalition still needs to assemble approximately 10 brigades, consisting of some 2,000 to 3,000 people in all, and wanted to first place them through additional training.

A basic training process takes eight weeks, Warren told reporters, with supplemental options for people like medics or snipers. But the number of troops that can be trained at once has varied.

“Over the last month or so, we’ve gotten about 900 police officers and roughly two brigades through training,” Warren told reporters. “This was the most graduates that we’ve had in a month. There’s been weeks or months where it’s been significantly less.”

He said the coalition has trained about 20,000 members of the Iraqi Security Forces, including police and tribal fighters. But he said even the ones who helped secure a key victory at Ramadi, a city that had been under Islamic State control, should receive additional training before Mosul.

“We believe that all of the forces that we’ve already trained and run through Ramadi are certainly capable of moving to Mosul, but we have made a decision that we want to run them through another cycle of training,” Warren told reporters. “Are they trained? Yes. Could they go to Mosul now? Yes. But we would prefer to give them additional training before they go.”

Ramadi, the capital of Anbar province, was captured by the Islamic State last year.

Iraqi officials announced that the military had raised the nation’s flag over a key government complex in Ramadi late in December, and forces have been working to secure outlying parts of the city ever since. On Friday, Warren told reporters that those efforts were continuing.

Warren also told reporters the coalition launched 676 airstrikes against the Islamic State in January, 522 of them in Iraq and 154 in Syria. Most of them were concentrated near Ramadi, Mosul and Raqqa, the Syrian city which the Islamic State considers its capital.