Islamic State has claimed responsibility for attacks on Iran's parliament and Ayatollah Khomeini's shrine.
Iran's state broadcaster IRIB reported that 12 people had been killed, quoting an Iranian official.
Attackers dressed as women burst through parliament's main entrance in central Tehran, the semi-official Tasnim news agency said.
Soon after the assault on parliament, another bomber detonated a suicide vest and a second attacker was shot dead near the shrine of the Republic's revered founder, Ayatollah Khomeini, a few kilometres south of the city.