U.S. Defense Secretary Jim Mattis says the Taliban's usage of civilian homes as fighting positions is forcing Afghan government forces to move slowly in expelling the insurgents from the city of Ghazni.

Mattis told reporters Tuesday during a visit to Brazil and Argentina that the fighting in Ghazni was continuing, five days after the Taliban overwhelmed defenses and pushed deep into the city, which is the capital of the province with the same name.

The United States has carried out airstrikes and sent military advisers to aid Afghan forces in the city.

Mattis says the attacks reveal nothing new about Taliban capabilities. He says it shows they remain focused on fighting among civilians.