A spokesman for provincial security chief Hazrat Hussain Mashriq said the number of casualties was unknown, Khaama Press reported.
The explosion occurred about 10 a.m. local time on Torkham-Jalalabad Road, the spokesman said.
No group had claimed responsibility.
McPhee, Cokas 'working on their marriage' after affair
LGBT community has 'bullied the American people': Bachmann