The commander of international forces in Afghanistan says the Islamic State group is actively recruiting in Afghanistan but is not yet operational there.

General John F. Campbell said on Saturday the group's sophisticated social media campaign is attracting Taliban fighters in Afghanistan and Pakistan who are disgruntled with the lack of progress in more than 10 years of fighting to overthrow the Kabul government.

He says many are pledging allegiance to the Islamic State group, which controls about a third of Syria and Iraq.

"It is absolutely a concern" Campbell says, though his statement contradicts some Afghan officials who have said the group is fighting in a number of regions in Afghanistan.

The IS presence in Afghanistan has grown considerably in the past six months, Campbell says.