kampala south sudanese soldier pass territory neighbor uganda launch assault rebel raise risk civil war spill neighbor east african countries south sudanese rebel witness say four-year-old conflict oil-rich south sudan world new country create africa big refugee crisis since 1994 rwandan genocide displace nearly third 12 million citizens one million seek refuge uganda late development rebel spokesman lam paul gabriel say government soldier sudan people liberation army spla cross uganda border post nimule friday drive ugandan towns moyo koboko cross back south sudan yei river state say ugandan military spla deny incursions spla troop uganda kaya town yei river 10 km miles ugandan border site fight military rebel saturday leave 19 people dead include american journalist reuters journalist uganda saw three spla pickup truck load uniform soldier wear red berets drive direction kaya friday another eyewitness ugandan border town moyo tell reuters saw truck men south sudanese military uniform move town friday morning ugandan military spokesman brigadier richard karemire deny account absolutely foreign military ugandan soil allow colonel santo domic chol spla spokesman also deny troop pass ugandan territory south sudanese soldier pass northwest uganda reach rebel-held territory residents say route allow avoid poor roads rebel blockade june men wear south sudanese military uniform launch town raid hamlet border uganda steal cattle first report attack ugandan soil since start south sudan civil war gabriel say believe ugandan government officially allow south sudan military use territory blame individual officials collude south sudan spoil relations us say uganda government need crack individuals uganda deploy military south sudan back president salva kiir shortly war begin late 2013. ugandan troop withdraw regionally-brokered 2015 peace deal collapse within months wednesday ugandan state-owned paper new vision report country beef security south sudan border ugandan military spokesman karemire deny story rebel say south sudan 's use uganda territory could spread instability