In a co-ordinated attack on the mausoleum of revolutionary leader Ayatollah Khomeini in the south of the city, a female suicide bomber blew herself up as more armed assailants entered the grounds.
"Fighters from Islamic state attacked Khomeini's shrine and the Iranian parliament in Tehran", said the terror group's news agency, AMAQ. In addition to the civil war raging in Yemen and the ongoing war in Iraq against the Islamic State militant group, Saudi Arabia and other Arab nations announced this week they were severing virtually all ties with the government of Qatar because of what they said was Qatar's support for terrorist groups.
The incident was quickly followed by reports of a gunman opening fire at Ayatollah Khomeini's tomb in southern Tehran.
The Iranian Intelligence Ministry says it foiled a third attack and is asking people to avoid public transportation, state broadcaster IRIB reports.More news: Wonder Woman breaks box office records after defying expectations
Hours after ISIS terrorists stormed the Iranian Parliament building in Tehran, local news agencies reported that the hostage situation has come to an end and all of the terrorists have been eliminated.
"I stand in solidarity with the President of Iranian Parliament and the Iranian people", European Parliament President Antonio Tajani tweeted. A security guard and a gardener were reportedly killed, and at least four people injured. The attackers, armed with assault rifles, killed a security guard at the shrine.
Attacks are highly rare in Tehran and other major cities though two Sunni militant groups, Jaish al-Adl and Jundallah, have been waging a deadly insurgency, mostly in more remote areas, for nearly a decade.
Heavy gunfire could be heard on videos filmed from outside parliament, and there are reports that a security guard has been killed. Another group of attackers, including a second suicide bomber, struck the shrine.
She said that the sophisticated and well organized attack targeted Iranian regime's symbol (Imam Khomeini shrine) and the symbol of the political system (parliament), hurt badly the country.More news: Where to get free doughnuts on National Doughnut Day
In a rare and stunning move, ISIS released video from inside the parliament building while the attack was under way. It described the shrine attackers as "terrorists" and said one carried out a suicide bombing.
Iran's deputy interior minister said the attackers dressed as women entered the parliament from the main gate.
Militant groups are also known to operate in Iran's southeastern Sistan-Baluchistan province, which borders Pakistan and has a large Sunni community.More news: British PM, rival face angry voters as election nears