The Islamic State issued a video on Wednesday threatening new attacks in the Iranian capital Tehran, local media reported.
A man wearing a black ski mask and holding an AK-47, seated alongside two others, made the threat in a video bearing the Islamic State's Amaq news agency logo.
The Islamic State, a Sunni Muslim group which has sought to establish a caliphate in the region, sees Iran as one of its enemies in the region.
The group killed at least 18 people in attacks on parliament in Tehran and the mausoleum of Ayatollah Khomeini on June 7.
Iran's Revolutionary Guards fired several missiles at Islamic State bases in Syria on June 18 in response to that attack. Iranian officials have also announced the arrests of dozens allegedly linked to the attacks.
Another portion of the video showed militants in black ski masks speaking out against Shi'ites in Arabic and threatening attacks against them in Iraq.