NEW : Pakistani Taliban takes credit for attack . Pakistani army spokesman : Militants strike government troops in northwest Afghanistan . two suspected militants died , others escape after long battle , spokesman says . ( CNN ) -- Violence has flared again in northwest Pakistan , where terrorists attacked army troops and two militant groups announced an alliance intent on starting a war against security forces . Lashkar-i-Islam says it 's joining forces with fellow militant group Pakistani Taliban .
NEW : Pakistani Taliban takes credit for attack . Pakistani army spokesman : Militants strike government troops in northwest Afghanistan . two suspected militants died , others escape after long battle , spokesman says . Lashkar-i-Islam says it 's joining forces with fellow militant group Pakistani Taliban .