U.N. judges have ruled prosecutors may present evidence from a recently discovered mass grave against former Bosnian Serb Gen. Ratko Mladic — a decision that will further delay a verdict at his war crimes trial.

Mladic, who is facing charges including genocide for atrocities committed by troops he led during the 1992-1995 Bosnian War, says he is innocent of wrongdoing. He has been on trial in the Hague since 2012.

The judges said Thursday that the evidence from the grave at Tomasica — where more than 400 bodies of Bosniak and Croat victims have been found since it was uncovered in October 2013 — is important to the case because it may show the large scale of killings in the area, and the role of Bosnia Serb forces under Mladic.