"News of another attack in Kabul is very saddening. Such attacks are unpardonable & deeply distressing. Condolences to families of deceased," he tweeted.
At least five people were killed today when a Taliban suicide car bomber struck near the entrance of Kabul's international airport, the latest in a wave of lethal bombings in the Afghan capital.
The Taliban, which claimed responsibility for the blast, have stepped up attacks amid a bitter leadership transition following the announcement of the death of their leader Mullah Omar.