Twin attacks on the Iranian parliament and Ayatollah Khomeini's mausoleum in the capital, Tehran, have killed at least 12 people and injured many more. The assault on the parliament appears to be over, after hours of intermittent gunfire there. A suicide bomber detonated a device at the mausoleum. Iranian officials say they managed to foil a third attack. The Islamic State group (IS) has claimed it carried out the attacks, which would be a first in Iran.