Update 2 | ISIS claims co-ordinated attacks in Tehran, 12 dead

Suicide bombers and gunmen attacked Iran's parliament and the Mausoleum of Ayatollah Khomeini in Tehran on Wednesday morning, killing at least 12 people in a twin assault at the heart of the Islamic Republic.

Islamic State claimed responsibility and released a video purporting to show gunmen inside the parliament building and one man, who appeared wounded, on the floor – a rare claim of responsibility while an attack was still going on.

The rare attacks were the first claimed by the hardline Sunni Muslim militant group inside the Shi'ite Muslim country. Iran is one of the powers leading the fight against Islamic State militants in neighbouring Iraq and, beyond that, Syria. ISIS consider Shiite Iran to be apostates.

The assaults began mid-morning when four gunmen dressed as women burst through parliament’s main entrance in central Tehran, deputy interior minister Mohammad Hossein Zolfaghari said, according to the semi-official Tasnim news agency. The attackers killed a security guard and one other person.

This image appears to show a child being lowered from a window of Iran's parliament building

"One of them was shot dead and another one detonated his suicide vest," Zolfaghari said.

At roughly the same time, a team of three or four assailants entered the grounds of the mausoleum of Ayatollah Ruhollah Khomeini, who led the 1979 Islamic revolution, killing a gardener and wounding several other people.

Iran's emergency services said a total of 12 people were killed in the two attacks and 39 wounded.

About five hours after the first reports, at around 3:00pm (11:30am CET), Iranian news agencies said four people who had attacked parliament were dead and the incident was over. Police said all the attackers had been killed by some five hours after it started.

Two of the attackers at the shrine, one of them a woman, blew themselves up, while another detonated a suicide vest on the fourth floor of the parliamentary office building.