BAGHDAD >> U.S. Secretary of State Mike Pompeo made a lightning visit to Baghdad today to show U.S. support for the Iraqi government as Washington steps up warnings to Iran against any action against American interests in the Middle East.

The unannounced trip began and ended after nightfall and under heavy security.

Pompeo’s visit came as the Trump administration is intensifying its pressure campaign against Iran. The U.S. said this week that it is rushing an aircraft carrier group to the Middle East to deter or respond to any Iranian attack. U.S. 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.

On the way to Baghdad today, Pompeo told reporters he would meet with Iraq’s president and prime minister to show them what he said is U.S. support for “a sovereign, independent” Iraq, free from the influence of neighboring Iran. He said he would also discuss with them unfinished business deals that he said would allow Iraq to wean itself from dependence on Iranian energy.

Pompeo would not be specific about the more recent threat information involving Iran, but said he would make the point in his meetings in Baghdad that any attack by Iran or its proxies on American forces in Iraq would affect the Iraqi government too.

The “campaign to continue to prevent ISIS terror inside of Iraq itself is something that’s very central … to the Iraqi government,” Pompeo said.

As tensions rise between Washington and Tehran, Baghdad in some ways is caught in the middle. Iraq has a close relationship with the U.S., which is leading the international coalition in the war against the Islamic State group in Iraq and Syria. More than 5,000 U.S. 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 antagonize its larger neighbor. Iran won the ear of many top Iraqi politicians after it stepped in to fill the political vacuum following the 2003 U.S. invasion. It also can count on the loyalty of several powerful Iraqi militias, which have fought previously against U.S. 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 U.S. interests from attacks by Iran and its proxy forces, Prime Minister Adel Abdul-Mahdi said today 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, President Donald Trump announced the U.S. would no longer exempt any countries from U.S. sanctions if they continue to buy Iranian oil. The U.S. 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.

Pompeo’s trip to Baghdad happened under tight security. Journalists accompanying Pompeo were not told of his new destination until his plane left for Baghdad and were not allowed to report on his whereabouts until after his plane took off for his next stop in London.