The European Union on Tuesday urged greater transparency in the run-up to nationwide elections in Guinea, warning of "chaotic" distribution of voting cards, a day after clashes in the capital.
With a week to go before the September 24 polls, EU election observers in Guinea said some citizens still did not know whether they had been registered to vote.
In a statement, the EU called on the national election commission to "be more transparent in order to reassure political actors and Guinea citizens over the integrity of each step in the electoral process".
The warning came a day after pro-government and opposition supporters clashed on the streets of Conakry, forcing Guinea's largest market to close as rioters pelted cars with stones and looted stores.
Legislative polls were initially due to have been held within six months of the swearing-in of President Alpha Conde in December 2010 but have been repeatedly delayed.
The west African nation's main opposition leader, Cellou Dalein Diallo, has accused the president's camp and the electoral commission of conniving to rig the vote.
Guinea's opposition warned on Sunday of nationwide protests if the electoral commission failed to meet its demands, meant to ensure that the polls are free and fair.
Diallo's party wants electoral lists to be published and the constituency map to be revamped, and has given the vote panel until Wednesday to meet its demands.
Conde was the country's first democratically elected president but opposing factions have failed to agree on how the polls should be organised.
Demonstrations on the issue have led to deadly violence, with more than 50 people killed since 2011.
Calm returned to Conakry on Tuesday, but there was a heavier than usual police presence in the city and many shops remained shut.
The last parliamentary elections in Guinea took place in June 2002 during the dictatorship of General Lansana Conte, who died in December 2008 after 24 years in power.