The fiery rhetoric comes hours after Iran launched missiles at two bases housing American and coalition troops in Iraq.
“General Soleimani fought heroically against ISIS, Al Nusra, Al Qaeda… if it weren’t for his war on terror, European capitals would be in great danger now,” Rouhani said.
“Our final answer to his assassination will be to kick all U.S. forces out of the region,” he added.
The tone in Rouhani’s remarks was a shift from comments Iranian Foreign Minister Javad Zarif made Tuesday evening, in which he said his country “took & concluded proportionate measures in self-defense” for the killing of Soleimani, striking the bases where the missiles targeting him were launched.
“We do not seek escalation or war, but will defend ourselves against any aggression,” Zarif had tweeted.
President Trump declared Wednesday that Iran “appears to be standing down” and that the strikes resulted in “no casualties.”
The office of Iraq’s president condemned the strikes Wednesday as a breach of the country’s sovereignty.
Barham Saleh's office said in a statement that the fate of U.S. troops in Iraq is an internal matter based on legal agreements to combat the Islamic State terrorist group.
The statement adds that Iraq "has previously declared its refusal to be a starting point for aggression against any country, and also refuses to be a source of threat to any of its neighbors."
The Iraqi prime minister has publicly said U.S. troops must leave after a drone strike killed Soleimani -- Iran's top military commander -- in Baghdad last Friday, and parliament has passed a non-binding resolution pushing for withdrawal.
NATO Secretary-General Jens Stoltenberg also condemned the strikes Wednesday, tweeting that the bloc is calling on Iran to “refrain from further violence.”
Four U.S. defense officials told Fox News that the military did not attempt to shoot down the ballistic missiles fired from Iran into Iraq because there were no American military assets in place to intercept them.
The Patriot and Avenger anti-missile defense systems are deployed to other locations in the Middle East, but not to the two Iraqi bases – al-Asad and Erbil – targeted by Iran. Officials say the American assets are in high demand and short supply around the world.
“For the past few years, our focus was defeating ISIS and keeping a light footprint in Iraq. We did not need air defense systems against ISIS,” as one official explained for why there was no U.S. missile defense systems in place at the Iraqi bases.
Fox News’ Lucas Tomlinson and the Associated Press contributed to this report.