Protesters angry with the postponement of Sunday's presidential election in parts of the Democratic Republic of Congo have attacked a clinic where possible Ebola cases are assessed.

The attack happened in the eastern city of Beni, one of three opposition areas where the vote has been postponed.

The electoral commission has cited the current Ebola outbreak as one of the reasons behind the postponement.

But opposition parties have accused the authorities of seeking to rig the vote.

Along with Beni, voting has been postponed until March in Butembo, also in the east and in Yumbi, which is in the west.

With President Joseph Kabila's successor due to be sworn in next month, it appears the votes of more than a million people could be discounted.

But in an interview with the BBC, Mr Kabila insisted that postponing the vote until after the final result was due to be declared was lawful.

"Don't worry, the law has catered for such issues," Mr Kabila said.

"I don't think there will be any major issues inasfar as the one-point-something million voters that you are talking about," he added.

DR Congo has not had a peaceful and democratic transfer of power since independence from Belgium in 1960.

Mr Kabila, who has been in office since 2001, was meant to have stepped down in 2016.

However, the election to choose his successor has been continually postponed, amid unrest and logistical difficulties in a nation with poor infrastructure.

Opposition supporters suspect Mr Kabila is trying to cling on to power. He denies the allegation and is backing former Interior Minister Emmanuel Ramazani Shadary in the election. (BBC)