Iranian Foreign Minister Javad Zarif said that Tehran took and accomplished proportionate measures in self-defence in accordance with the UN Charter when it targeted the US military bases in Iraq.
He added that Iran is not seeking any war or escalation, but will act in defence against any aggression.
Approximately 35 missiles were launched by the IRGC towards military bases in Ayn al-Asad and Erbil, where American military personnel is deployed at the moment. Later, a second series of rockets was fired towards US targets in Iraq, Iranian state TV reported.
Tehran dubbed the operation "Martyr Soleimani", designed as a "hard revenge" for Maj. Gen. Qasem Soleimani, who was killed in the targeted US attack on the Baghdadi International Airport on 3 January. Iranian Supreme Leader Ali Khamenei warned later that "harsh vengeance awaits the criminals" that killed the commander, who was one of the most prominent political figures in the country.
There have been no casualties reported so far on the US personnel side, Washington officials said. An assessment of the damage and casualties is taking place.
President Donald Trump is going to make a statement on the attacks on Wednesday morning.
The late Tuesday attacks on US assets in Iraq have sparked great concerns in the Middle East, as well as around the world. The American forces in Syria and Israeli Air and Defence forces have been reportedly put on high alert, flights have been banned over the Persian Gulf, and Japanese Prime Minister Shinzo Abe has cancelled his planned Mideast tour.
The reports of Iran's attacks also had a major financial effect. China stocks were shaken by the tensions in the Mideast, as the Shanghai Composite and CSI300 indexes dropped by more than 0.5 percent. The US stock futures on the S&P 500 Index have declined by more than 1 percent.
Crude oil prices have instead surged reaching $65.50 a barrel, and gold prices have been hitting their highest level since 2013 ever since the death of Gen. Soleimani on Friday.