Two U.N. experts are appealing to Guatemala's judicial authorities to "prevent any further attempt at interference, obstruction of justice or manipulation of the law" in the genocide trial of former dictator Efrain Rios Montt and a former intelligence chief.

Thursday's statement by the experts on genocide prevention and transitional justice comes after a court this week said the 89-year-old former dictator Efrain Rios Montt can stand trial in January despite having dementia.

Rios Montt is accused of genocide and crimes against humanity during his dictatorship in 1982 and 1983 at the height of Guatemala's civil war. José Mauricio Rodríguez Sánchez faces similar charges.

The U.N. experts are criticizing "delaying strategies" and "alleged threats and pressure against judges and prosecutors" in the case.