The Islamic State group claimed its first attacks in Iran on Wednesday, June 7 as gunmen and suicide bombers killed at least five people in twin assaults on parliament and the tomb of the country's revolutionary founder in Tehran, AFP reports.

Dozens of people were also wounded in the attacks, with continuing gunfire several hours after they began.

A security guard and one other person were killed when four gunmen burst into Tehran's parliament complex with rifles and a pistol, according to the ISNA news agency.

One of the attackers blew himself up on the fourth floor of the parliament office building as a standoff with police continued for several hours.

In the coordinated mid-morning attack, a gardener was reported dead and several more injured when armed assailants entered the grounds of Ruhollah Khomeini mausoleum in the south of the city.

Two attackers -- at least one female -- blew themselves up outside the shrine, according to local media.

Iran's emergency services said they were dealing with 33 injured from the attacks and that two people had died from their injuries in hospital.

IS claimed the attacks in a report from its Amaq propaganda agency which said: "Fighters from the Islamic State attacked the Khomeini mausoleum and the parliament building in Tehran."

It also claimed two suicide bombers had blown themselves up at the shrine.

Parliament was in session as the attacks unfolded, with live footage showing members continuing with routine business even as gun battles were reported in surrounding office buildings and snipers took position on nearby rooftops.

Speaker Ali Larijani dismissed the attacks, saying they were a "trivial matter" and that security forces were dealing with them.

Intensified gunfire was heard from the neighbouring offices as Fars news agency reported police had launched an assault. A picture on social media showed police helping staff escape through windows.