The US Army is pushing to get precision mortars developed and deployed to the field in Afghanistan as soon as possible. Mortars are lighter and can be towed by a HMMWV or MRAP, or carried and fired from inside M113 or Stryker APCs, making them easier to deploy than heavier cannon artillery.
When indirect fire support is needed against enemies who are dug in along mountain ridgelines and other high positions, or in an urban area where which building you hit matters a great deal, getting the job done requires precision artillery. That capability has already come to MLRS rockets (M30/31 GMLRS, ATACMS), and 155mm artillery shells (Excalibur), and has been deployed to great effect on the front lines by American forces and their allies. Now it is coming to the USA’s 120mm mortars as well.