Terror attacks on Iran parliament and Khomeini tomb claimed by Islamic State
Terrorists have launched attacks on Iran's parliament and the tomb of its revolutionary leader, Ayatollah Ruhollah Khomeini.
The Islamic State group claimed responsibility for the onslaught in which a t least 12 people were killed and 40 wounded.
Tehran police chief General Hossein Sajedinia announced late on Wednesday night that five suspects had been detained for interrogation, the semi-official Isna news agency reported.
Reza Seifollahi, of the country's Supreme National Security Council, was quoted by the independent Shargh daily as saying the perpetrators of the attacks were Iranian nationals.
The bloodshed shocked the country and came as emboldened Sunni Arab states, backed by US president Donald Trump, are hardening their stance against Shiite-ruled Iran.
In recent years, Tehran has been heavily involved in conflicts in Syria and Iraq against the Islamic State, but had remained untouched by IS violence around the world.
Iran has also battled Saudi-backed Sunni groups in both countries.
Iran's powerful Revolutionary Guard indirectly blamed Saudi Arabia for the attacks.
A statement issued on Wednesday evening stopped short of alleging direct Saudi involvement but called it "meaningful" that the attacks followed Mr Trump's visit to Saudi Arabia, where he strongly asserted Washington's support for Riyadh.
The statement said Saudi Arabia "constantly supports" terrorists including the Islamic State group, adding that the IS claim of responsibility "reveals (Saudi Arabia's) hand in this barbaric action."
The "spilled blood of the innocent will not remain unavenged", the Revolutionary Guard statement said.
Ayatollah Ali Khamenei, the country's supreme leader, used the attacks to defend Tehran's involvement in wars abroad.
He told a group of students that if "Iran had not resisted", it would have faced even more troubles.
"The Iranian nation will go forward," he added.
The violence began in mid-morning when assailants with Kalashnikov rifles and explosives stormed the parliament complex where a legislative session had been in progress.
The siege lasted for hours, and one of the attackers blew himself up inside, according to Iran's state TV.
Images circulating in Iranian media showed gunmen held rifles near the windows of the complex.
One showed a toddler being handed through a first-floor window to safety outside as an armed man looks on.
The IS group's Aamaq news agency released a 24-second video purportedly shot inside the complex, showing a bloody, lifeless body on the floor next to a desk.
An Associated Press reporter saw several police snipers on the roofs of nearby buildings.
Police helicopters circled the parliament and all mobile phone lines from inside were disconnected.
Shops in the area were closed as gunfire rang out and officials urged people to avoid public transportation.
Witnesses said the attackers fired from the parliament building's fourth floor at people in the streets.
"I was passing by one of the streets. I thought that children were playing with fireworks, but I realised people are hiding and lying down on the streets," Ebrahim Ghanimi, who was around the parliament building, told the AP.
"With the help of a taxi driver, I reached a nearby alley."
As the parliament attack unfolded, gunmen and suicide bombers also struck outside Khomeini's mausoleum on Tehran's southern outskirts.
The ayatollah led the 1979 Islamic Revolution that toppled the Western-backed shah to become Iran's first supreme leader until his death in 1989.
Iran's state broadcaster said a security guard was killed at the tomb and that one of the attackers was slain by security guards.
A woman was also arrested. The revered shrine was not damaged.
The Interior Ministry said six assailants were killed, four at the parliament and two at the tomb.
A senior Interior Ministry official told Iran's state TV the male attackers wore women's attire.
Parliament Speaker Ali Larijani called the attacks a cowardly act.
Saudi Arabia and Iran regularly accuse each other of supporting extremists in the region.
Saudi Arabia has long pointed to the absence of IS attacks in Iran as a sign of Tehran's culpability.
For its part, Iran has cited Saudi Arabia's support for jihadists and its backing of hard-line Sunni fighters in Syria.