Iran says it has killed the mastermind behind the twin attacks on its parliament and the mausoleum of Ayatollah Khomeini, which left 17 dead and injured 50.

Eight others have been arrested in the Alborz Province in connection with the attacks, according to reports by state news agencies.

The terrorist attacks – the first in many years on Iranian soil – have been claimed by the jihadist group Islamic State in Iraq and Syria (Isis), which has denounced Shia Iran as a nation of heretics in the past.

Iran’s intelligence minister Mahmoud Alavi said security forces had killed the commander of the operation, which saw five men dressed as women open fire on visitors to the Majlis-e Shoura and the mausoleum. Two of the attackers eventually detonated explosive vests themselves, while the others were shot dead by security forces.

It is unclear where the mastermind was killed, although it is believed one of the attackers came from the Kurdistan region of Iran.

Iran has blamed Saudi Arabia, citing statements made against the Islamic Republic by the kingdom’s foreign minister and deputy crown prince as having instigated the attacks.

Neighbouring Iraq also witnessed terror attacks two days later, near the Shia holy shrine of Karbala located to the south of Baghdad, which killed 30.