- 8 people injured in twin attacks in Iran: report
- 4 men armed with rifles, pistol were reported to be inside parliament
- Local media said female suicide attacker blew herself up outside tomb
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.
A gardener was reported dead and several more injured when armed assailants entered the grounds of Khomeini's mausoleum.
A female suicide bomber blew herself up outside the shrine while another woman was arrested carrying six grenades, according to the Mizanonline news agency. A little while later, a second suicide bomber detonated explosives outside the mausoleum.
Parliament was in session when the attacks unfolded, with live footage showing members continuing with business even as gun battles were reported in surrounding office buildings. Speaker Ali Larijani dismissed the attacks, saying they were a "trivial matter" and that security forces were dealing with them.
An official at Khomeini's mausoleum in south Tehran said "three or four" people had entered via the western entrance and opened fire.
The shrine lies around 20 km from parliament and houses the body of Khomeini, who led the Islamic revolution in 1979.
The city was on lockdown, with streets blocked and parts of the metro closed. Journalists were kept away from the shrine by police.
Interior Minister Abdolrahman Fazli told ISNA he had convened a special meeting of the country's security council.
Iran has been singled out as a target by jihadist groups, including ISIS, but has largely escaped attacks within its urban centres.
Iran, the predominant Shiite power, has been helping both Iraq and President Bashar al-Assad's regime in Syria to battle the Sunni extremist group.
ISIS is under increasing pressure in both countries, having lost significant territory in the face of offensives now targeting its last two major urban bastions, Raqa in Syria and Mosul in Iraq.
ISIS published a rare video in Persian in March, warning that it "will conquer Iran and restore it to the Sunni Muslim nation as it was before."