Guinea's election chief on Friday called off a weekend presidential runoff, yet another delay of a tense poll already overshadowed by violent protests and bitter disagreements.
"It is not possible to hold the presidential election on Sunday," said electoral chief Siaka Toumani Sangare.
He did not say when a new date would be announced.
The announcement comes amid growing violence and a U.N. report alleging human rights violations by Guinean security forces.
A doctor at Conakry's main hospital said Thursday night that he treated several men who appeared to have been hurt in a scuffle between supporters of presidential candidates Cellou Dalein Diallo and Alpha Conde. The doctor, who did not give his full name, said two of the victims were comatose when they arrived with severe head injuries and that one later died.
A spokesman for Diallo's party, Souleymane Bah, said men from his party were attacked as they returned from a party meeting.
Earlier this week, junta leader Gen. Sekouba Konate named Sangare, a Malian citizen, to head the electoral commission after disagreements over the commission's makeup threatened to delay the presidential runoff, scheduled for Sunday. Since then, officials learned that 17 computers that were to tabulate poll results were missing.
During protests earlier this week, security forces fired at unarmed protesters _ shooting some at point-blank range, the Geneva-based U.N. human rights office said in a statement.
One man was killed and at least 62 were wounded during demonstrations in Conakry during the week. The U.N. said authorities severely beat protesters and arbitrarily detained an unknown number of people and kept them in undisclosed locations. Among the victims was a 7-year-old schoolboy who was shot in the head by a stray bullet and remains in a coma.
The statement said some of those responsible for the violence appear to be members of a special police unit charged with safeguarding the election.
A policeman and a human rights worker also described other violent acts by security forces.
Thierno Maadjou Sow, president of a Guinean human rights group, said he knows of at least two rapes which he described as particularly violent.
"They were taken, brutalized, raped and imprisoned," he said, adding that his group is still gathering information.
A police officer said he saw two of his colleagues rape a young girl. He asked that his name not be used because of the sensitivity of the situation. He said he also saw his colleagues strike a pregnant woman in her stomach, causing bleeding and the possible loss of her baby.
Security forces are feared in Guinea. On Sept. 28, 2009, soldiers sealed off the exits to the national soccer stadium where tens of thousands of protesters had gathered to demand an end to military rule. The troops entered and opened fire with assault rifles. A U.N. commission said 156 people were killed or disappeared and at least 109 women were raped or subjected to other forms of sexual violence, which may constitute crimes against humanity.
The U.N. human rights office said some of the latest violence appears to be ethnically motivated.
Diallo is a Peul, the country's largest ethnic group, which has never had one of its own in power. Last year, the Peul were explicitly targeted during the stadium massacre. Conde is a Malinke _ a group heavily represented in the army, as well as in the junta blamed for the massacre.
The U.N. agency called on political leaders to restrain their supporters, "both within the security forces and among the general population," while respecting their right to assemble and protest peacefully.
Also Friday, top election official Lounceny Camara was sentenced to a year's imprisonment and a fine of approximately $300 for manipulating the first round of elections, held on June 27.
Sunday's vote would have been the West African country's chance to freely elect its own leader for the first time since winning independence from France in 1958.