A gunman on the loose inside the Iranian parliament building has detonated his suicide vest on the fourth floor of the building, according to local media reports.

Twin terror strikes hit the capital of Tehran on Wednesday morning. Local media reports at least eight people have been killed since gunmen stormed parliament and two suicide bombs were detonated at the tomb of Ayatollah Khomeini in the south of the city. Isis issued a claim of responsibility for the ongoing incidents.

Four people have been taken hostage in parliament, Tasnim news agency said. There are conflicting reports as to how many gunmen are involved in both attacks. At least one assailant was shot dead by police attempting to escape the parliament building.

It was reported earlier that four attackers descended on the mausoleum of Ayatollah Khomeini, killing a security guard and detonating a suicide bomb which injured four members of the public. However, Tehran's governor later said that one assailant had blown themselves up, and one had been killed by police.

Isis, which views majority-Shia Iran as a heretical state, has ramped up anti-Iranian propaganda in recent months.

The attacks on Wednesday are the first major assaults carried out by the Sunni group inside the country.

The Tehran bombings occur during the holy Muslim month of Ramadan, in which Isis tells would-be jihadists the rewards for martyrdom are increased.