Donald Trump's chief foreign policy advisor made an unannounced trip to Baghdad which sees both its neighbour Iran and the US as key allies.
The US Secretary of State Mike Pompeo made an unannounced and sudden trip to Iraq on Tuesday as Washington escalated tensions with Iran by sending an aircraft carrier to the Persian Gulf.
The trip began and ended after nightfall and under heavy security. He cancelled a planned meeting with German Chancellor Angela Merkel before travelling to Baghdad.
Pompeo's visit came as the US President Donald Trump's administration is intensifying its pressure campaign against Iran.
The US said this week that it is rushing an aircraft carrier group to the Middle East to deter or respond to any Iranian attack.
US officials have said there are indications Iran is planning to retaliate for the Trump administration's stepped-up sanctions on the country, although the threat information remains vague.
History weighs heavily against Washington's claim. The invasion of Iraq in 2003 was based on false intelligence reports that the then-Iraqi regime of Saddam Hussain was hoarding weapons of mass destruction.
According to Reuters, Pompeo said US "wants Iraq to be independent and not beholden to any country" and that "Iran is escalating its activity" in the region.
In Iraq, Pompeo met Iraqi President Barham Salih and Prime Minister Adel Abdul Mahdi.
Details about what was discussed have yet to come out as journalists traveling with Pompeo were not even allowed to report until he left for his next stop in London.
As tensions rise between Washington and Tehran, Baghdad in some ways is caught in the middle. Iraq has a close relationship with the US, which is leading the international coalition in the war against Daesh group in Iraq and Syria.
More than 5,000 American troops are stationed on Iraqi soil.
But Iraq is also tightly enmeshed with Iran in trade, security and political matters, and it has been loath to antagonise its larger neighbor.
Iran won the ear of many top Iraqi politicians after it stepped in to fill the political vacuum following the 2003 US invasion.
It also can count on the loyalty of several powerful Iraqi militias, which have fought previously against US forces in the country and on the side of Iran's allies in Syria in that country's civil war.
Responding to a question about whether Iraq could protect US interests from attacks by Iran and its proxy forces, Prime Minister Mahdi said Tuesday that Iraq takes its responsibilities seriously. "This is an obligation that Iraq honors," he said.
The Trump administration has made several recent moves to squeeze Iran.
Last month, Trump announced the US would no longer exempt any country from its sanctions if they continue to buy Iranian oil.
Washington also designated Iran's Revolutionary Guard as a terrorist group, the first ever for an entire division of another government.
Trump withdrew from the Obama administration's landmark nuclear deal with Iran in May 2018 and, in the months that followed, re-imposed punishing sanctions, including those targeting Iran's oil, shipping and banking sectors.
European Union and other world powers that were also part of the deal have opposed US moves but they haven't been able to pacify Tehran.