A rift between the Afghan government and Nato officials over a rocket attack in Helmand province appears to be deepening. <br /><br />Afghanistan's president says 52 civilians were killed in an attack by international forces.<br /><br />But the Nato-led force says a preliminary investigation has not revealed any civilian casualties.<br /><br />Al Jazeera's James Bays reports. (July 28, 2010)
