Warning followed rocket attacks on Green Zone and US base, after senior Iranian commander was killed in US attack.
US President Donald Trump has threatened to hit 52 Iranian sites "very hard" if Iran attacked Americans or United States assets following a US raid on Friday that killed head of the Quds Force Qassem Soleimani and an Iraqi militia leader.
Showing no sign of an effort to ease tensions in the region, Trump took to Twitter to warn that the US had "targeted 52 Iranian sites" and that some were "at a very high level & important to Iran & the Iranian culture, and those targets, and Iran itself, WILL BE HIT VERY FAST AND VERY HARD."
"The USA wants no more threats!" Trump said.
The 52 targets represented the 52 Americans who were held hostage in Iran for 444 days after being seized at the US embassy in Tehran in November 1979, he added.
Tensions have escalated since Friday, when the US killed Iranian commander Soleimani and top Iraqi paramilitary chief Abu Mahdi al-Muhandis in a drone attack on their convoy as it drove out of Baghdad's international airport.
Several rockets fell in and around Baghdad on Saturday night, including inside the capital's heavily-fortified Green Zone and the Balad airbase housing US troops.
No casualties were reported in the rocket attacks, which were confirmed by a US military spokesman, Colonel Myles B Caggins III. He said no troops had been injured but Iraqi civilians could have been harmed.
Donald J. Trump
@realDonaldTrump
Iran is talking very boldly about targeting certain USA assets as revenge for our ridding the world of their terrorist leader who had just killed an American, & badly wounded many others, not to mention all of the people he had killed over his lifetime, including recently....