It's not known if an explosion in Afghanistan yesterday was an attack, or just more old shells blowing up (more common than terrorist attacks in Kabul). Some obscure groups have taken "credit" for the attack, but that's typical, and often meaningless. 

Five 107mm rockets fired at a US base in southeast Afghanistan missed (which is normal) and injured several civilians living nearby. Sweeps of the backcountry down there continue to uncover caches of weapons, including 107mm rockets.