Iran parliament attack
Members of Iranian forces take cover during an attack on the Iranian parliament in central Tehran, Iran Reuters

Iran has arrested over 40 suspects in connection with twin terror attacks on Tehran last week as the country's security was stepped up to combat militant groups.

The so-called Islamic State claimed responsibility for the suicide bombings and gun attacks on the Iranian parliament, and the mausoleum of the Islamic Republic's founder, Ayatollah Ruhollah Khomeini, on 7 June.

Late on Saturday (10 June), Iranian intelligence minister Mahmoud Alavi confirmed on local television that 43 suspects had been arrested in connection with the attack.

The minister also said operations to "neutralise terrorist cells" were ongoing.

Earlier on Sunday, the country's Fars news agency reported that Iran had killed the "mastermind of the attacks" who was based in the border regions.

Fars also claimed that five of the gunmen and bombers were Iranian members of Islamic State who had fought in the militants' strongholds in Syria and Iraq.

The attack last week was the worst terror atrocity faced by the country since 1981, when a bomb planted by an Iranian opposition group in Tehran killed 27 Iranian members of parliament and dozens of officials.

However, in Wednesday's attacks, no member of the parliament was killed as the attackers were unable to breach the building's out perimeter and failed to reach the main complex.