International negotiators have urged the militant Basque separatist group ETA to lay down its weapons, ending a 40-year campaign of violence, according to the BBC. The call from delegates including ex-UN chief Kofi Annan came at a conference in northern Spain seen as a possible prelude to ETA’s dissolution. Neither the Spanish government nor ETA was officially represented. ETA has killed more than 800 people since the 70s, but has been weakened by arrests and is observing a ceasefire. Spanish ministers have called on ETA to seize the opportunity to end the violence.