Conakry - At least 13 people were killed in a week of violence in Guinea before and after its contested presidential election, with the security forces responsible for the deaths of unarmed civilians, Amnesty International said in a report published on Thursday.The toll covers the period October 8-13, the days surrounding the October 11 vote which, according to the country's Independent National Electoral Commission (CENI), handed victory and another five-year term to incumbent Alpha Conde.His main rival, opposition leader and former premier Cellou Dalein Diallo, has refused to recognise the outcome and urged supporters to take to the streets against what he labelled an "illegal" election tainted by mismanagement and fraud.Rights group Amnesty spoke of "fears that future protests could lead to more deaths unless security forces show restraint and those suspected of firing on civilians are brought to justice".Clear evidenceAmnesty listed six people killed in election-related violence in Guinea's capital city Conakry, including two victims shot in the back, and seven other fatalities in "violence between supporters" elsewhere in the country."There is clear evidence that members of Guinea's security forces were responsible for the death and injury of unarmed civilians," said Francois Patuel, Amnesty International's West Africa researcher."There could be no justification for firing at these unarmed people, and no excuse for failing to hold those suspected of criminal responsibility to account," he added.A previous AFP toll, collated from various sources, was 10 dead throughout the country ahead of the vote.All seven defeated presidential hopefuls have dismissed the election as a charade and refused to recognise the official results, which gave Alpha Conde 57.85% of the vote, averting the need for a second round run-off.Witness statementsAmnesty stressed that not all the violence came from the authorities but added that "as long as the use of firearms by the security forces against the population continues to be tolerated by the authorities, it will be impossible to build trust or put an end to Guinea's history of electoral violence."Amnesty added that none of those killed by the security forces had been involved in violence and all were unarmed.The findings were backed up by witness statements.One of the witnesses cited said; "We were chatting next to the workshop where our friends were working. A pick-up truck from the gendarmerie drove-up the street and seven gendarmes stormed out carrying rifles... we got scared and we ran away. They shot us and hit our friend in the back. We found him on a rubbish dump in the morning."Amnesty International said it had documented more than 350 deaths, and more than 1 750 people injured, during demonstrations in the country over the past decade."Most of these have been protesters, and in some cases bystanders, killed or injured at the hands of security forces."