(CNN) Iran has slammed US President Donald Trump's response to Wednesday's twin terror attacks in Tehran as "repugnant", as the death toll from the ISIS-claimed assaults rose to 16.
"Repugnant WH (White House) statement & Senate sanctions as Iranians counter terror backed by US clients. Iranian people reject such US claims of friendship," Iranian Foreign Minister Javad Zarif tweeted Thursday.
Zarif was responding to President Trump's statement following the bombings that said, "We grieve and pray for the innocent victims of the terrorist attacks in Iran, and for the Iranian people who are going through such challenging times."
It then added, "We underscore that states that sponsor terrorism risk falling victim to the evil they promote."
Six attackers mounted simultaneous gun and suicide bomb assaults on Iran's Parliament building and the tomb of the republic's revolutionary founder Ayatollah Khomeini in one of the most audacious assaults to hit Tehran in decades.
All six of the attackers, who all died in the assault, have been identified. Five of them had previously fought with ISIS in Mosul and Raqqa, the Iranian Intelligence Ministry said in a statement Thursday.
The five men were associated with "Takfiri groups" -- a term referring to extremist Sunnis -- and left Iran after joining ISIS, the statement said.
The men entered Iran last year under the command of a man known as "Abu Ayesha." They intended to carry out attacks at religious sites but were thwarted after key members of their cell were apprehended. Abu Ayesha was killed at the time, according to the Iranian Intelligence Ministry.
The armed assailants, apparently dressed as women, attacked the parliament buildings on Wednesday morning equipped with assault rifles, handguns and suicide vests, killing security guards and ordinary people before taking hostages in the upper floors of the building.
Security forces then laid siege to the parliament for several hours. Three of the gunmen were shot dead in an exchange of gunfire, while another blew himself up.
In the attack at the mausoleum, one suicide bomber blew himself up while the second one was killed in a gunfight, according to the semi-official Tasnim news agency.
The ISIS media wing, Amaq, claimed "fighters with the Islamic State" carried out the assault. It was the first time that ISIS, a Sunni Muslim group fighting Iranian-backed militias in Syria, has claimed responsibility for an attack in Iran and the choice of locations were also highly symbolic.
Iran's Intelligence Ministry said Thursday it will soon release the names and pictures of the gunmen involved in the terrorist attacks, all of whom were killed on Wednesday, Tasnim reported.
Iran's Islamic Revolutionary Guard Corps vowed revenge for the attack, which it says was supported by Saudi Arabia, and tied it to the visit of President Trump to Saudi Arabia in May.
The Revolutionary Guards' accusation comes at a time of heightened Saudi-Iranian tensions following a regional rift with Qatar.
Saudi Arabia, Bahrain, Egypt and the United Arab Emirates cut ties with Qatar this week and has blocked several of the country's media outlets. The rift was over comments allegedly made by Qatari Emir Sheikh Tamim bin Hamad Al Thani hailing Iran as an "Islamic power" and criticizing Trump's policy toward Tehran.
The Emir's alleged comments appeared on Qatar's official news agency, but Qatar said the website was hacked and the report fabricated by the culprits.