UN human rights experts on Monday welcomed a recent Guatemalan court ruling that the deaths of 1,771 ethnic Ixil Mayan people between 1983-1984 constituted a “genocide.”

“Impunity for perpetrators is unacceptable,” said UN experts about the ruling. “It is essential that judicial processes respect international standards in determining the responsibilities of the perpetrators and masterminds of serious violations of international human rights law and international humanitarian law.”

The deaths occurred during the 36-year-long Guatemalan Civil War, in which 200,000 civilians were killed. It was proven that under Operation Sofia, former President José Efraín Ríos Montt had ordered the army to annihilate the entire Ixil population of a Guatemalan state. Montt was convicted in 2013, but that verdict was overturned for procedural errors. Trial resumed last year, but Montt died in April 2018, before the case was concluded.

The UN has sought to label the victims’ murders as genocide since 1999, when the Human Rights office deputized a commission to report on the crimes. Eventually, more than 9,000 witness came forward and gave testimony.

“We urge the Government to take the necessary urgent measures to guarantee judicial independence and the protection of judges, prosecutors, witnesses, victims and plaintiffs who participate in these important judicial processes,” concluded the UN experts.