Guatemala's Supreme Court has suspended the presidential candidacy of former military leader Jose Efrain Rios Montt.
Mr Rios Montt is accused of ordering killings
The court made the decision after an opposition candidate appealed against the former strongman's candidacy.
The suspension means that Mr Rios Montt will be unable to run as the candidate of the ruling Republican Front unless he, in turn, succeeds in an appeal.
Earlier on Sunday, thousands of people marched through Guatemala City to protest against the retired general - who governed for 18 months following a coup in 1982.
Human rights groups accuse him of having ordered thousands of killings and kidnappings during his rule.
Mr Rios Montt, 77, was barred from running in 1990 and 1995 because Guatemala's 1985 constitution bars former coup leaders from running for the presidency.
This year the electoral tribunal and the supreme court also ruled that he could not contest November's election.
However Mr Rios Montt's lawyers have argued that the 1985 constitution cannot be applied retroactively.
Last week they succeeded in getting the ban overturned by the constitutional court - Guatemala's highest jurisdiction.