kabul rocket attack afghan religious school kill 20 taliban insurgents exchange fire security force officials say friday add children among victims insurgents take shelter school compound central eastern province wardak 35 km 20 miles southwest capital kabul air strike hit late wednesday officials say international force conduct air strike across country immediately available comment abdul rahman mangal spokesman governor wardak say civilian casualties add pupils go home air strike foreign troop step air strike afghanistan recent months afghan force struggle resilient taliban insurgency taliban seek reimpose strict islamic law 2001 ouster u.s.-led troop afghan air strike kill 20 taliban religious school officials