Iraqi security officials said an explosion targeted a site used by the US military next to Baghdad airport late Tuesday, one day before an expected visit by Iran’s president.

The expected visit by Iranian President Masoud Pezeshkian to Baghdad Wednesday would be his first official trip abroad since taking office.

Iraq’s security media cell said in a statement that an explosion was heard at 11 p.m. at the airport, in an area used by advisers to the US-led international coalition.

The statement said Iraqi security forces were unable to determine the “type or causes of the explosion, and no party has claimed responsibility for it.” It added that the incident was under investigation and civilian air traffic continued as normal.

There was no immediate information on damage or casualties.

US officials did not immediately respond to requests for comment.

An Iraqi security official at the airport, who spoke on condition of anonymity because he was not authorized to speak publicly about the matter, said that officials who were at the airport preparing for Pezeshkian’s visit heard “the sound of two strong strikes,” which apparently targeted a logistics support site for the coalition.

Over the past 11 months, Iranian-backed Iraqi militias have periodically targeted bases housing US forces in Iraq and have said that the strikes were in retaliation for Washington’s support of Israel in the war in Gaza.

One of those militias, Kataib Hezbollah, appeared to be trying to distance itself from Tuesday night’s strike.

Jaafar al-Husseini, the group’s spokesperson, said in a statement that the targeting of the airport was “carried out by suspicious hands, and its aim is to disrupt the Iranian president’s visit to Baghdad.”