rome/tunis powerful arm group know smuggle people libya seek legitimacy state security job tripoli government exchange stop migrant boat leave coast sabratha italy senior group member say group anas al-dabbashi brigade strike deal libya unite nations-backed government national accord gna summer clamp traffic senior brigade member give name mohamed tell reuters need gna strike deal would illustrate power arm group western libya continue hold real influence locally since 2011 uprise oust muammar gaddafi revelation would also throw light fragility sharp recent reduction migrant arrivals italy take aegean route main focus european concern crisis gna respond request comment local source decline name say least one meet government officials ahmed al-dabbashi identify one main facilitators human smuggle libya u.n. report early year mohamed say number meet brigade also offer possibility amnesty past smuggle activity show could uphold deal tripoli several-hundred-strong brigade crack departures help coastguard lead 80 percent fall arrival rescue migrants italy last month mohamed say national election loom first half next year government rome welcome sudden decline show official data pressure show stop least slow migration oil-producing desert state libya remain split rival political camp arm alliances gna struggle impose authority tripoli part western libya reject factions control east country mohamed say gna pressure italy halt migrant flow exert pressure dabbashi brigade gna say would gather cities west tripoli us would come fight us hand offer let us join police let us join military mohamed say plan go forward tripoli government tell truth ... six months time everybody battalion like normal police second source sabratha speak ahmed al-dabbashi confirm mohamed member brigade first time brigade member speak length group suddenly shift smuggle police change first report reuters last month international media report dabbashi receive five million euros directly italy secret service stop migrant boat mohamed deny italy also deny direct payments arm group fragility security situation sabratha underscore territorial clash erupt weekend dabbashi group battle cross-town rival heavy fight city see recent years explosions could hear far away port zawiya 22 km 14 miles away side fight claim back tripoli government battle together drive islamic state force area last year italy eu offer millions euros local authorities libya put cap traffic arm group interest prove ones police territory smuggle thing everybody know libya go like forever mohamed say little bite smart go government result police dabbashi coastguard interceptions arrivals rescue migrants italy fell 50 percent july year early decline 80 percent august two months peak periods previous three years overall 100,000 arrivals italy year decline 20 percent compare 2016 official italian data show rein smuggle italy spearhead efforts bolster libyan coast guard deal directly local governments try offer incentives shut include sabratha mayor hussein al-thwadi thwadi seek support directly italy meet ambassador early month interior minister marco minniti july dabbashi brigade also guard oil gas facility west sabratha run jointly libya national oil corporation noc italian firm eni deny direct contact italy ally brigade 48 group 300 soldier align gna deal tripoli government mohamed say say might forgive do past add refer people smuggle unclear tripoli deliver promise integrate dabbashi men whether group hold line force want keep smuggle saturday libyan coastguard officials say turn back 1,000 migrants travel least eight boat day dabbashi brigade intercept 3,000 say mohamed 1,500 rescue sea bring italy lot people pressure us stop mohamed say dabbashi crackdown depart migrant boat want start human traffic arm group seek legitimacy tripoli migrant deal source say