By Abdoulaye Massalaki
NIAMEY (Reuters) - Thousands of anti-government protesters marched in Niger's capital on Sunday to denounce what they say are irregularities in voter lists ahead of presidential elections in early 2016.
Marchers carried banners with slogans such as "The people stand up for clean elections" and "No to dictatorship" and demanded a full audit of the electoral register.
Niger, a poor, uranium-producing country in the Sahel band of West Africa, is set to hold presidential elections in February with President Mahamadou Issoufou expected to seek a second five-year mandate.
Issoufou, a key Western ally against radical Islamist groups, is widely expected to triumph over a fragmented opposition to win a second mandate. His ruling PNDS party has forecast a one-round victory.
This is despite a failure to secure regions like Diffa, where Nigeria-based Boko Haram militants have increased cross-border attacks in recent months, prompting the authorities to declare a state of emergency.
Opposition parties have regularly criticised vote preparations, alleging that thousands of people have been excluded from a national census, and condemning delays in amalgamating voter lists.
Niger's interior minister Hassoumi Massaoudou has previously defended the lists and accused the opposition of trying to delay the election calendar, in defiance of the constitution.
"Issoufou has never planned on organising credible elections with a credible electoral register," said opposition leader Seyni Oumarou, at a meeting with political groups and civil society leaders that immediately followed the march.
Organisers said that between 20,000-25,000 people attended the protest while police officials declined to comment. A march organised last weekend was banned by the authorities.
Criminality also remains rampant in the vast country, home to drugs, weapons and migrant smugglers operating across the ancient caravan routes of the Sahara.
Much will hinge on whether Issoufou's main rival and former head of parliament Hama Amadou will be allowed to stand as a candidate.
The government has previously said that Amadou, who left the country following allegations of trafficking babies from Nigeria, would be arrested if he returns.
On Sunday, Oumarou said he will return. "He will be certainly be in Niamey," he said. Amadou has denied the allegations against him.
(This version of the story bears a correction in the final paragraph to show Amadou has yet to return to Niger)
(Writing by Emma Farge; Editing by Andrew Bolton)