A political standoff in the Democratic Republic of Congo has deepened after the country’s top court backed the contested presidential election victory of Felix Tshisekedi.

His main rival has rejected the ruling, called for protests and declared himself leader.

As Mr Tshisekedi's supporters celebrated the ruling in the streets of Democratic Republic of Congo's capital, runner-up Martin Fayulu said the decision had opened the way to a "constitutional coup d'etat", raising fears of more violence.

Following the court decision, the African Union postponed a visit by a high-level delegation to the Congolese capital, Kinshasa, that had been scheduled for tomorrow to discuss the crisis.

It has previously expressed "serious concerns" about the vote and called for the results to be delayed.

Last month's election was meant to mark the first democratic transfer of power in the vast central African country, where conflicts have regularly destabilised the region.

However monitors pointed to major flaws in the poll.

Unrest over the vote has already killed 34 people, wounded 59 and led to 241 "arbitrary arrests" in the past week, according to the UN human rights office.

In the early hours of this morning, the Constitutional Court ruled that a legal challenge to the result filed by Mr Fayulu was inadmissible.

"Felix Tshisekedi will become the fifth president of the republic," government spokesman Lambert Mende said as he welcomed the judgement.

Mr Fayulu issued statements dismissing the ruling.

"The constitutional court has just confirmed that it serves a dictatorial regime ... by validating false results, (and enabling) a constitutional coup d'etat," he said in one.

"I am now considering myself as the sole legitimate President of the Democratic Republic of Congo," he added in another statement.

He called for people to mount peaceful demonstrations - though the streets of the capital were calm this afternoon.

Mr Fayulu says Mr Tshisekedi and outgoing President Joseph Kabila made a deal to cheat him out of a more than 60% win – an accusation they both dismiss.

The provisional results, announced on 10 January, showed Mr Tshisekedi winning with a slim margin over Mr Fayulu.

In a speech, Mr Tshisekedi welcomed the victory and said he would seek to mend divisions in the country.