A militant affiliated with the faction told Reuters the group attacked Damadola district of the Bajaur tribal area in Pakistan's northwest, where the military has been battling a militant insurgency since 2007, late on Saturday.
"Our men destroyed the post, set it on fire and left it after our operation was complete," he said by telephone.
Two Pakistani intelligence officials confirmed a checkpoint had been attacked, but there were no casualties.
The Pakistani government says that Islamic State, a group founded in Syria and Iraq in 2013, does not have a credible presence in the country. Several smaller militant groups and factions of the Pakistani Taliban have, however, pledged allegiance to Islamic State and its leader Abu Bakr al-Baghdadi since last year.
So far, Islamic State has not formally accepted any of those pledges, nor has its central leadership claimed responsibility for any attacks carried out in Pakistan.