A Katyusha rocket hit an Iraqi military base hosting U.S. forces near Baghdad’s international airport on Wednesday, Iraqi security and military sources said.

An Iraqi military statement said it found a rocket launcher with one rocket in al-Jihad district in western Baghdad near the airport.

The sources said that nobody was hurt in the incident.

U.S. officials have warned in recent weeks they expected an uptick in attacks against U.S. forces in Iraq and Syria, in part because of the second anniversary of the killing of top Iranian general Qassem Soleimani.

While there were no immediate claims of responsibility for recent attacks, Iraqi militia groups aligned with Iran vowed to retaliate for killing Soleimani and Iraqi militia commander Abu Mahdi al-Muhandis.

Wednesday’s attack is the second one this week targeting the base near Baghdad’s international airport after an attack by two drones was foiled on Monday.

Two explosive-laden drones were also shot down on Tuesday by Iraq’s air defenses as they approached the Ain al-Asad air base, which hosts U.S. forces, west of Baghdad.

Soleimani was killed on Jan. 3, 2020 in a drone strike near Baghdad airport ordered by then-U.S. president Donald Trump.

Iranian President Ebrahim Raisi said on Monday that Trump must face trial for the killing or Tehran would take revenge.