BAGHDAD (AP) — At least three rockets targeted the U.S. Embassy in Baghdad's heavily fortified Green Zone on Sunday, Iraqi security officials said, sparking fears of renewed unrest as next month's anniversary of the slaying of an Iranian general draws near.

The embassy's C-RAM defense system was used to destroy the rockets mid-air, three Iraqi security officials said, with damage caused to property and parked cars. It was not immediately clear if there were any casualties. The officials spoke on condition of anonymity in line with regulations.

The C-RAM system was installed by the U.S. over the summer as armed groups stepped up rocket attacks targeting the embassy and its premises.

The U.S. withdrew some staff from its embassy in Baghdad earlier this month, temporarily reducing personnel ahead of the first anniversary of the Washington-directed killing of Iranian General Qassim Soleimani outside Baghdad's airport on Jan. 3. U.S. officials said the decision stemmed from concerns about a possible retaliatory strike.

Soleimani's killing sparked outrage and led Iraq’s parliament to pass a non-binding resolution days later calling for the expulsion of all foreign troops from Iraq.

The frequency of rocket attacks have frustrated the Trump administration. Iran-backed militia groups have been blamed for orchestrating the attacks.

In September, Washington warned Iraq that it will close its embassy in Baghdad if the government fails to take decisive action to end rocket and other attacks by Iranian-backed militias on American and allied interests in the country.