Rouhani said earlier Americans would face consequences for killing Soleimani “not only today, but also in the coming years.”
Rouhani’s remarks came on the same day mourners in neighboring Iraq had chanted “Death to America” at a funeral procession for Soleimani and an Iraqi militia leader who died with him in a US airstrike in Iraq early Friday.
“The Americans did not understand what grave mistake they committed,” Rouhani said while visiting the house of Soleimani’s family in Tehran, according to a statement his office released.
In a phone conversation with Turkish President Recep Tayyip Erdogan, Rouhani said Iran’s neighbors in the region should work in unison against the US presence there or the whole area will be in jeopardy, Iranian state news agency IRNA reported.
Maj. Gen. Ismail Qaani, who served for years alongside Soleimani, has been appointed his replacement.
It marks a major escalation in regional tensions that have pitted Tehran against Washington and its allies in the Middle East.
Trump said Soleimani was plotting “imminent and sinister attacks” on Americans.
Iran says it will fight back
Rockets hit parts of Baghdad on Saturday, including the parade grounds in Baghdad’s fortified Green Zone and the Al-Jadriya area just south of the Green Zone, injuring no one, the Iraqi army said. The Green Zone contains Parliament, ministries and foreign embassies.
Rockets targeted Balad Air Base, which houses US and Iraqi forces and contractors, the Iraqi army said. No injuries were reported.
Separately, an Iraqi civilian contractor there told CNN that four rockets landed outside the base’s southern gate.
During Rouhani’s visit with Soleimani’s family Saturday, Soleimani’s daughter asked him: “Who will take revenge for my father?”
“Everyone will take revenge,” he replied, in video aired by Iranian state television.
In a letter to the United Nations, Iran described the attack as state terrorism and an unlawful criminal act. European officials and the UN have called for de-escalation.
He said the strike will increase threats to US interests.
“Today the administration announced we’re sending 3,000 more troops to the region,” he said. “So, clearly the administration recognizes that this action has actually dramatically increased the risks in the Middle East, increased the risks of an attack from Iran.”
Acting Homeland Security Secretary Chad Wolf issued a new National Terrorism Advisory System bulletin. “Iran maintains a robust cyber program and can execute cyberattacks against the United States,” according to the bulletin, which expires January 18.
Wolf maintained in a statement that there is “no specific, credible threat against the homeland.”
Mourners chant ‘Death to America’ at funeral procession
In Iraq’s capital on Saturday, thousands of people attended a funeral procession, mourning Soleimani and al-Muhandis as they chanted “Death to America.”
Mourners wept as they walked alongside the vehicle carrying his coffin down the streets of Baghdad. Some carried signs that read, “We are all Muhandis and Soleimani.”
Iraqi Prime Minister Adil Abdul Mahdi was among the crowd of mourners walking next to the cars carrying the coffins.
Some women carrying flags of the Iraqi Popular Mobilization Forces erupted into tears when the slain commanders were mentioned. Many mourners said the attack strengthened their resolve to expel US forces from Iraq.
“This strike killed our heroes, but it created a thousand more Hajji Soleimanis and Muhandises,” said Assifa Abbas, 50, a mother of three PMF fighters. “If Parliament doesn’t vote to expel US troops, they will see the true face of the Iraqi street.”
Abbas walked in the procession with an image of al-Muhandis and Soleimani taped on her black chador. She said she would refuse to allow her sons back into her house until they pushed the “last American” from Iraq.
Former Parliament member Fawzi Akram, from Iraq’s Turkmen ethnic minority, predicted the attack would end US dominance in the country. “The map of a new Iraq will be drawn with the blood of these martyrs,” Akram said.
Mourner Mohammad al-Fadli said the killings came as an “indescribable shock.” “These are the people who got rid of ISIS for us,” al-Fadli said.
Iraq’s anti-corruption demonstrators also aren’t happy about the US strike
In another part of Baghdad, some anti-government demonstrators have been demanding, among other things, an end to heavy-handed Iranian influence in Iraq. But many haven’t been happy about the US strike.
Since the anti-corruption protests began in October, Iraqi security forces have tried to violently quash them, killing hundreds of demonstrators and wounding many more.
Still, people at Baghdad’s main protest site, Tahrir Square, said Saturday that the US should not have conducted an attack on their soil.
“We are the people of Iraq. We don’t want outsiders to rule us,” protester Muthana Salman said.
CNN’s Faith Karimi, Pamela Brown, Jomana Karasheh, Zachary Cohen, Sharif Paget, Arwa Damon, Sara Mazloumsaki, Artemis Moshtaghian and Kareem Khadder contributed to this report.