Several rockets have fallen near the United States embassy in Baghdad injuring five people.
The rockets fell in the Iraqi capital's heavily fortified Green Zone which houses government buildings and foreign missions.
"Several rockets targeting Celebration Square and the Jadriya area in Baghdad, and the Balad air base in Salahuddin province, with no loss of life. Further details to come," the Iraqi military said in a statement.
There are currently not believed to be any deaths.
It comes a day after Donald Trump ordered the drone execution of top Iranian General Qassem Soleimani at Baghdad Airport.
After his death, the country's supreme leader Ali Khamenei sparked fears of war as he announced revenge, adding: "I and the government and the nation of Iran strongly condemn this American crime."
The phrase "World War 3" began trending on Twitter and searches for the same sentence also spiked on Google within hours of the air strike in Iraq.
Iraqi Prime Minister Adel Abdul Mahdi today declared three days of national mourning for Soleimani, Iraqi militia leader Abu Mahdi al-Muhandis, and others killed in a US air strike in Baghdad.
"Prime Minister and Commander in Chief Adel Abdul Mahdi orders the deceleration of national mourning for the souls of the martyrs for three days as of Saturday," his office said in a statement.
Thousands of mourners chanting "death to America" took to the streets of Baghdad after the US president ordered the killing.
Iran then raised a red flag over a mosque hinting impending revenge on the US.
Iran raised the red flag over the Holy Dome of Jamkarān Mosque, believed to be a warning of a battle to come.
It reportedly reads: "Those who want to avenge the blood of Hussein."
Leader of the Islamic Revolution in Iran Imam Sayyed on Friday vowed “severe revenge” in response to the killing of Soleimani, Daily Express reports.
Millions feared the assassination could spark a chain of events ending in a full-scale combat.
Donald Trump said after the strike: “What the United States did yesterday should have been done long ago. A lot of lives would have been saved.
“Just recently, Soleimani led the brutal repression of protesters in Iran, where more than 1,000 innocent civilians were tortured and killed by their own government.
“We took action last night to stop a war. We did not take action to start a war.”
British nationals are advised not to travel to Iraq, apart from essential travel to its Kurdistan Region, while all but essential travel to Iran is warned against.
The guidance was bolstered on Saturday after the United States announced it was sending nearly 3,000 extra troops to the region.
