An IS statement issued late Friday described Satnam Singh, 45, as “polytheist” and said he was shot dead by IS members.
Pakistani officials have denied any organized IS presence in the country but the extremist group has claimed a number of attacks on security forces, mosques, political rallies and religious minorities in recent years.
Police said Singh was gunned down Thursday in Peshawar, the provincial capital of Khyber Pakhtunkhwa province bordering Afghanistan. The gunmen fled the scene.
Singh, an herbalist, had lived in the city for the past 20 years and ran a small clinic selling herbal medicine.
The assailants opened fire at Singh inside the clinic, according to Sardar Harpal Singh, a local community leader. He denounced the incident and demanded the arrest of those involved in the killing. The two are not related.
The majority of Sikhs migrated from what is now Pakistan to neighboring India in 1947, the year British rule of the subcontinent ended and Pakistan was created as a homeland for Muslims in the region. Thousands of them stayed in Pakistan, where they generally live peacefully. But isolated attacks on religious minorities including Sikhs have continued.