The United States used low-flying combat aircraft against Libyan leader Muammar Gaddafi's ground troops, the Pentagon said on Monday, but denied it was directly supporting the rebels.
"We have employed A-10s and AC-130s over the weekend," US vice-admiral Bill Gortney, director of the US military's Joint Staff, told reporters, without giving specifics about targets.
The A-10 is an aircraft designed for close air support, especially against tanks and armored vehicles. The AC-130 "Spooky" is a transport aircraft modified for close combat. Among its guns is a 105mm cannon.
Unlike the long-range guided missile attacks that have targeted command centers and anti-aircraft defenses, these aircraft are designed for close-range assaults against ground troops.
The rebel offensive in the past week has been greatly facilitated by the coalition's strikes against Gaddafi's forces.
But Gortney said the US actions are only in support of the UN-backed resolutions to protect Libyan civilians.
"We're not in direct support of the opposition, that's not part of our mandate and we're not coordinating with the opposition," he said.