They returned fire with 120mm tank rounds,
Here's why. Air cover was likely VERY unnecessary:
XM1028 120mm Canister Tank Cartridge
The Tank Cartridge, 120mm, Canister, XM1028, is a tank round comprised of 1150 (est.) tungsten balls, which are expelled upon muzzle exit. There is no fuse on this round. While the dispersion pattern increases with range as the velocity of the balls decreases, the dense tungsten balls are used to minimize the velocity fall-off. This program responds to the USFK urgency of need signed by the CINC in Dec ‘99. RAPT Initiative Funding to be used for 6.0M in FY02 to accelerate development by one year earlier than previously planned.
This round meets urgent CINC, USFK requirements to provide effective rapid lethal reaction against massed assaulting infantry armed with hand held anti-tank and automatic weapons at close range (500 meters or less) thereby improving survivability. Additionally, this round will significantly increase the tank’s lethality and enhance the tank crew’s survivability. This additional capability will give the Abrams Tank the ability to survive RPG ambushes and to fully support friendly infantry assaults. 