A USA diplomatic outpost and major regional airport near the southwest Iraqi city of Basra was the target of a rocket attack early Friday morning, amid continuing violent civil unrest in the oil-rich city.
"I have advised the Government of Iran that the United States will hold Iran directly responsible for any harm to Americans or to our diplomatic facilities in Iraq or elsewhere and whether perpetrated by Iranian forces directly or by associated proxy militias".
The decision, which followed rocket attacks and violent protests in the crumbling port city, could increase tensions between the USA and Iran.
The ministry's statement came a day after the US State Department made a decision to close its consulate in Basra, 550 km south of the capital, Baghdad.
Iraq's Foreign Ministry said it regretted the decision and urged foreign diplomats not to pay attention to "what is being circulated to undermine the climate of security and stability accompanying Iraq's relations with the countries of the world".
For the first time in several years, mortar shells also landed this month inside Baghdad's heavily fortified Green Zone, which houses parliament, government buildings and many foreign embassies.
However, it is quite crystal that USA officials' "childish justifications" are part of the country's adventurism and plot to depict Iraq as an insecure country to exert pressure on the Arab country's government, the Iranian spokesperson said.
The consulate closure is temporary and involves relocating diplomatic personnel.
The United States of America has given Iran notice that it will retaliate to any violence against its nationals, entities or partners. Neighbouring Iran is the other major outside power present in Iraq, alongside bitter foe the United States which led the 2003 invasion that toppled veteran dictator Saddam Hussein.
The Iranian government denied being involved in the incidents in Iraq, according to the state media.
An Iraqi protester holds up an Iranian flag as another sets it on fire, next to a portrait depicting Iran's former and current Supreme Leaders Ayatollah Khomeini and Khamenei, during demonstrations against the government and the lack of basic services in Basra on September 7, 2018.