The Taliban are likely to keep up their recent surge of violence in advance of scheduled parliamentary elections in October, but Afghan defenses will not break, US Defense Secretary Jim Mattis said on Thursday.

In his most detailed comments on the Taliban's assault on the city of Ghazni since it began on 10 August, Mattis said the Taliban had six objectives in and around the city and failed to seize any of them.

He would not specify the six sites.

"We now know that the enemy had six objectives in Ghazni. They failed to seize any one of the six locations in the area. It's been principally an information operation to grab a lot of press attention. They've been successful. The operation itself, there are still some hiding out in houses trying to get resupplied, that sort of thing. So clearance operations continue. But at least right now we do not have hunger in the town. Commerce going on. That sort of thing,” he said. 

The insurgents likely were trying to gain leverage in advance of an expected ceasefire offer by Afghan President Ashraf Ghani, the US defense chief said, adding they likely were also hoping to sow fear in advance of the October elections.

In Ghazni, the provincial police chief earlier on Thursday said that roads were being cleared of mines planted by Taliban who temporarily held entire neighborhoods of the city that they had besieged.

The fighting continued for five days with more than 100 members of the Afghan National Security forces killed and 20 civilians.

Scores of Taliban were also killed, according to Afghan officials.

Mattis said some Taliban fighters were still holed up in houses in the city "trying to get resupplied".

“It's not just propaganda, Carla. What, and if you go back and study insurgencies, when they get close to negotiation or an imposed end, in other words they can't sustain, any number of reasons why they think the clock is running - here at this point there is a proposed ceasefire or is it an election coming up - you'll often see an uptick in violence, because that's the only thing they can do,” he said. 

But businesses were reopening, and overall, "it's much more stable", showing that the Taliban had fallen short.

Mattis made the comments as he talked to reporters flying with him to Bogota, Colombia, where he was winding up a weeklong tour of South America.