F-16 warplanes attacked a radar at a military civilian airport near Basra in southern Iraq today, US defence officials said.
It was the second such raid against Baghdad's air defences this week.
A brief announcement by the US military's Central Command in Tampa, Florida, which controls operations in the gulf region, said only that the warplanes had attacked a military radar in southern Iraq at about 17.30 GMT and after dark in Iraq.
But US officials said privately the radar was located at a civilian airfield.
A similar raid was carried out in the south by both US and British aircraft on Tuesday against facilities used to guide Iraqi fighter jets.
The Pentagon said it had also hit military air defence targets in Iraq last Saturday in retaliation for increasing attempts by Iraq's President Saddam Hussein to shoot down a western warplane.
Iraq said it shot down an unmanned US Predator reconnaissance aircraft over southern Iraq on Monday.
Iraqi media reported the shooting down with glee.
"This slap on America's ugly face was a surprise to its arrogant administration. The Americans will have to retire these kind of planes and stop them from harming our proud nation," said an editorial in al-Jumhuriyanewspaper.