evidence: Sudan-South Sudan border: Clashes kill dozens in disputed Abyei region [...] South Sudan and Sudan jointly administer Abyei, and both claim ownership to the region in a dispute that has remained unresolved since the South's independence in 2011. [...] The UK, Norway and the United States, the international trio that sponsored South Sudan's independence, said on Monday that they were "deeply concerned by the escalation of violence in recent months between communities living in and around" Abyei.