Iran and the US are in a tense battle for influence in Iraq, where Tehran has powerful allies and Washington has close ties to the government.
Bases in Iraq housing US troops and foreign embassies, particularly the American mission, have been targeted in more than two dozen rocket attacks since October that Washington has blamed on Iran-backed armed groups.
Tensions have risen even sharply since Trump withdrew from a landmark nuclear agreement in 2018 and re-imposed sweeping sanctions.
On Wednesday, Trump warned Iran that it would pay a “heavy price” in the event of further attacks on US troops.
He tweeted that “upon information and belief, Iran or its proxies are planning a sneak attack on U.S. troops and/or assets in Iraq.”
In response, Zarif wrote on Twitter that “Iran has FRIENDS: No one can have MILLIONS of ‘proxies'”
Iran responded angrily to the US Patriot deployment warning that Washington risked leading the Middle East to disaster in the midst of the Coronavirus pandemic.
Iran has repeatedly called on the Trump administration to reverse its sanctions policy, which has been opposed even by US allies, particularly since the COVID-19 pandemic hit.
