The tiny Horn of Africa nation of Djibouti held parliamentary elections on Friday but an opposition spokesman denounced what he described as massive fraud.
Even though the opposition boycotted previous elections, it has presented a rare unified front to face the coalition supporting President Ismael Omar Guelleh, who has been in power since 1999.
The polls, which had been scheduled to close at 6 pm local time (1500 GMT), were extended by an hour in a move the opposition says was "with instructions to presidents of polling stations," Daher Ahmed Farah, opposition spokesman for the Union for National Salvation (USN), told AFP when contacted from Nairobi.
He added that USN delegates had been expelled from several venues especially in the capital, which is home to three quarters of the country's population.
Farah also said that members of the Republican Guard, an army unit responsible for presidential security, voted multiple times in various polling stations within the city.
"Two members of the USN, including a candidate, were also arrested and detained by the police for one hour before being released," he added.
The allegations could not be independently verified from other sources and no government official was contacted in Djibouti.
This is the first poll since 2003 in which opposition groups have decided to forge a coalition, taking part as the Union for National Salvation (USN).
The ruling party Union for the Presidential Majority (UMP) party said in a message on Twitter that there was one incident of stone throwing but otherwise there was "calm in all the polling stations".
Djibouti, with a population of some 800,000, occupies a strategic position at the entry to the Red Sea and is home to the biggest French and United States military bases in Africa.
"The voting started early in the morning and has been calm and peaceful," said Fowsi Abokar, a resident and businessman in the capital, Djibouti city.
"The process of the election has been orderly, people did not have to queue for very long," said Abdulahi Jama, who said voters at some polling stations in the desert villages outside the capital had already finished.
However, later in the day it was not possible to connect either by mobile or landline telephones.
"They cut the telephone network," said Hachin-Ahmed Loita, a spokesman for the opposition Union for Democracy and Justice (UDJ) party, speaking from Paris, adding he had not been able to contact anyone in the country.
President Ismael Omar Guelleh, 65, in power since 1999 and whose Union for the Presidential Majority (UMP) held all 65 seats in the last parliament, said the elections were a "milestone for the democratisation" of the country.
Guelleh, in a message broadcast Friday on national television, urged citizens to vote for his UMP, which he said was leading Djibouti towards "peace and prosperity."
Preliminary results are expected Saturday.
Djibouti, an arid and extremely hot country, derives most of its revenue from its port, from land rented out for the Western military bases as well as from livestock and the banking sector.
Guelleh -- only the second president since independence from France in 1977 -- was re-elected for a third five-year term in April 2011 after the constitution was revised to allow him another stint in office.