US President Donald Trump warned Iran of a "high price" on Wednesday if he or his allies attack US troops stationed there in Iraq.
"We do not want hostility, but if they are hostile to us, they will regret it as if they have never regretted anything," he said of Iran at a White House press conference on the coronavirus pandemic.
"If this happens, Iran will actually pay a very high price!" Trump tweeted earlier in the day.
The US president also wrote: "According to information and belief, Iran or its deputies are planning a secret attack on US troops and / or assets in Iraq."
It was not clear whether Trump believed Washington actually had information about such a plan.
Tensions between archenemies – already high since Trump abandoned a pioneering nuclear deal and imposed extensive sanctions in 2018 – have increased since the U.S. killed Maj. Gen. Qasem Soleimani of Tehran in a drone attack outside Baghdad airport in January.
The US and Iran are in a tense battle for influence in Iraq, where Tehran has powerful allies, including among armed militias, and Washington has close ties to the government.
Around 7,500 foreign troops are in Iraq under the US-led coalition to help local troops fight jihadist groups. However, these numbers will be reduced significantly this month.
The alliance is temporarily bringing some trainers home as a precaution against the coronavirus pandemic and is also leaving some Iraqi bases altogether.
These bases and foreign embassies, particularly the American mission, have been attacked in more than two dozen rocket attacks since late October.
The attacks that the US has accused of an Iranian-backed armed group have raised fears of proxy war on Iraqi soil.
Iran had imposed US sanctions on Wednesday earlier than its own virus death toll exceeded 3,000.
Tehran has repeatedly urged Washington to reverse its policies, which the US allies have opposed, particularly since the COVID-19 pandemic.
Iranian President Hassan Rouhani accused Washington of missing a "historic opportunity" to lift sanctions.
"This was a humanitarian issue. Nobody would have blamed her for the retreat," he said.
Medicines and medical devices are technically exempt from U.S. sanctions, but purchases are often blocked by banks' unwillingness to process purchases for fear of imposing heavy penalties in the United States.
(Except for the headline, this story was not edited by NDTV staff and published from a syndicated feed.)