The Khyber Pakhtunkhwa Counter Terrorism Department (CTD) claimed to have arrested two campaigners of ISIS from Notia Bazaar in Peshawar late on Friday, Dawn online reported.
Leaflets and pamphlets urging people to join ISIS were also recovered from them.
Cases have been registered against the suspects, who allegedly were trained in Afghanistan, under the Anti-Terrorism Act, 1997.
Security has been intensified in Peshawar after the arrest of ISIS suspects. ISIS had recently announced it was setting itself up for operations in Pakistan and Afghanistan.
ISIS pamphlets were also recovered from Safoora Goth carnage in Karachi where a former jail superintendent of Hyderabad police Aijaz Haider was gunned down on May 15.
The Pakistan foreign office has recently admitted ISIS activities inside Pakistan, it also admitted that the radical Islamist group posed a "serious threat" to the country.