Five militants responsible for deadly attacks in Tehran spent time in IS' territories, Iran says

Five Iranian militants who carried out twin attacks in Tehran on Wednesday were members of the Islamic State group and had been to its strongholds in Iraq and Syria, Iran said on Thursday.

The attacks on Tehran's parliament complex and the shrine of revolutionary leader Ayatollah Ruhollah Khomeini left more than 17 people dead and wounded more than 50 people in an attack first claimed by IS in Iran.

"The five known terrorists... after joining the Daesh (IS) terrorist group, left the country and participated in crimes carried out by this terrorist group in Mosul and Raqqa," the ministry said in a statement.

It suggested there were only five attackers rather than the six originally reported. 

The ministry released their photographs and first names, and said they were part of a network that entered Iran in July-August 2016 under the leadership of "high-ranking Daesh commander" Abu Aisha intending to carry out "terrorist operations in religious cities".

Abu Aisha was killed and the network forced to flee the country, the statement said. It was not clear when the five men returned to Iran ahead of Wednesday's attacks. 

The statement contradicts claims by Iran's elite Republican Guard that Saudi Arabia was responsible for the attacks.

Iran denounced Donald Trump's reaction to the attacks as "repugnant" after the US president said the nation was reaping what it sowed.

Trump said the US would "grieve and pray" for the victims, but added: "We underscore that states that sponsor terrorism risk falling victim to the evil they promote."

That was condemned by Iranian Foreign Minister Mohammad Javad Zarif, who tweeted: "Repugnant WH (White House) statement... as Iranians counter terror backed by US clients."