Tehran - Gunmen and suicide bombers stormed Iran's parliament and the shrine of its revolutionary leader on Wednesday, killing 12 people in the first attacks in the country claimed by the Islamic State group.Dozens of people were wounded in the attacks, which ended after a standoff lasting several hours as the gunmen holed up in parliamentary office buildings. ISIS released a video of the attackers from inside the building via its Amaq propaganda agency - a rare claim of responsibility while an attack was still going on.Police said all the attackers had been killed by around 15:00 (10:30 GMT), about five hours after it started.The Sunni jihadists of ISIS consider Shi'ite Iran to be apostates, and Tehran is deeply involved in fighting the group in both Syria and Iraq. The assaults began mid-morning when four gunmen burst into the parliament complex in the centre of Tehran, killing a security guard and one other person, according to the ISNA news agency.An interior ministry official said they were dressed as women and entered through the visitors' entrance.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. 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. A picture on social media showed police helping staff escape through windows.