Burundi's government must ensure that crucial elections, scheduled for this year, are violence-free and open to the opposition, a senior UN official said Wednesday.

Several opposition figures are facing criminal charges seen as politically-motivated ahead of local, legislative and presidential polls to be held between May and June.

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"Organising peaceful and credible elections is one of the most pressing challenges facing Burundi this year," UN Under Secretary General Jeffrey Feltman told the Security Council.

"Burundians, regardless of party affiliation, must be free to exercise their civil and political rights," said Feltman.

Concerns over the election process in Burundi, a country still traumatized by 13 years of civil war, were heightened after the government boycotted the launch of a UN observer mission this month.

Burundi's foreign ministry cited technical problems with the mission and argued it lacked the authority to verify final results.

Feltman said he expected the government to endorse the election observers' mission and sign a document to that effect soon.

Burundi emerged in 2006 from a brutal 13-year civil war and its political climate remains fractious ahead of the polls.
The last elections in 2010 were boycotted by most opposition parties.