KABUL, Afghanistan — Afghanistan accused Pakistan of killing at least 400 people in an airstrike on a drug rehabilitation hospital in the Afghan capital late Monday. It marked a dramatic escalation of a conflict that began late last month and has seen repeated cross-border clashes as well as airstrikes inside Afghanistan. International calls for a ceasefire have gone unheeded.Pakistan dismissed the accusation that it had hit a hospital, saying its strikes, which were also conducted in eastern Afghanistan, did not hit any civilian sites.Afghanistan's deputy government spokesperson Hamdulla…READ FULL ARTICLE