Rescue crews are still digging bodies out of the rubble of a drug rehabilitation hospital in the Afghan capital Tuesday morning, after officials there said an overnight Pakistani airstrike killed at least 400 people at the facility. Pakistan has denied Afghanistan’s accusation that it targeted a hospital, saying its strikes, which were also conducted in eastern Afghanistan on Monday, did not hit any civilian sites. The late Monday night strike on the Omid Addiction Treatment Hospital, a 2,000-bed facility, marks a dramatic escalation of a conflict that began between Afghanistan and Pakistan late last month. The fighting has seen repeated cross-border clashes as well as airstrikes inside Afghanistan. International calls for a ceasefire have gone unheeded.