Iran's Parliament Speaker calls US international version of ISIS

A police officer stands guard as vehicles drive in front of Iran's parliament building in Tehran, Iran, Thursday, May 8, 2017.

"Iranian people reject such US claims of friendship", he said, hinting in the tweet that the terror attacks were "backed by USA clients".

In an outpouring of support against Iran, dozens of countries have condemned Wednesday's attack on the country's parliament and on the mausoleum of the Ayatollah Khomeini.

Meantime, Intelligence Minister Mahmoud Alawi said over the past two days, the ministry has identified the hideout of the perpetrators of Tehran attacks. Iranians will not be intimidated by such attacks.

According to the statement, the team of five attackers had previously belonged to Sunni extremist groups inside Iran but later joined IS, where they went to fight in Mosul, Iraq, and Raqqa, Syria. The attackers had entered Iran at some point a year ago, the ministry said without providing precise dates.

Ali Larijani, Iran's Parliament Speaker, called the attacks "a cowardly act" and reportedly downplayed the tragedies as a "minor issue". That came after Mohammad Hossein Zolfaghari, a deputy Interior Minister, told state TV that "law enforcement activities may increase".

Medical sources said Thursday that the death toll in the two attacks rose to 17, adding 50 people had been injured.

Bombers and gunmen killed 17 people in Iran's parliament and near the mausoleum of the Islamic Republic's founder, Ayatollah Khomeini, on Wednesday, in rare strikes on the capital that exacerbated regional tensions. Strongly Shiite Iran is giving help to the fight against ISIL in both Syria and Iraq.

"Terrorism respects no borders, and we remind the Trump administration that Iranians held vigils for the American victims of terrorism after the September 11th attacks".

A senior official, who also asked not to be named, said the attacks would push Iran toward "a harsher regional policy".

It then added, "We underscore that states that sponsor terrorism risk falling victim to the evil they promote". The US decision was confirmed on the same day as the Tehran attacks.

"Iranian people reject such USA claims of friendship", Zarif tweeted.

Iranian security officials counter that it is their regional rival Saudi Arabia - a close United States ally - that is responsible for funding and spreading the extremism that underpins IS.

It appears that United States and Saudi Arabia are being blamed by Iranian parliamentarians for the terrorist attacks on Wednesday.

The "spilled blood of the innocent will not remain unavenged", the Revolutionary Guard statement said. ISIS has threatened Saudi Arabia with attacks.

The Trump administration has taken a much harder line toward Iran than its predecessor, describing it as the top state sponsor of terrorism in the world and backing the view of allies Israel and Saudi Arabia that Iran is the chief threat to stability in the region.