Rwanda has cut diplomatic ties with Belgium, saying it has been "consistently undermined" by the European nation during the ongoing conflict in the Democratic Republic of Congo.

Brussels has been leading calls for European nations to sanction Rwanda over its support for the M23, a rebel group at the centre of DR Congo's crisis.

The authorities in Kigali, Rwanda's capital, have given Belgian diplomats 48 hours to leave the country.

Belgium, which is the former colonial power, has said it will respond to these measures and labelled Rwanda's decision "disproportionate".

Despite assertions from the UN and US, Rwanda has denied backing the M23.

In its statement on Monday, Kigali accused Brussels of attempting to "sustain its neo-colonial delusions".

"Belgium has clearly taken sides in a regional conflict and continues to systematically mobilise against Rwanda in different forums, using lies and manipulation to secure an unjustified hostile opinion of Rwanda, in an attempt to destabilise both Rwanda and the region," the statement said.

Belgian Foreign Minister Maxime Prevot responded to Rwanda's measures on social media, saying: "This is disproportionate and shows that when we disagree with Rwanda they prefer not to engage in dialogue."

Prevot said Rwandan diplomats in Belgium will be declared "persona non grata".

This declaration can lead to the removal of diplomatic status and often results in the expulsion or the withdrawal of recognition of envoys.

Before Kigali cut ties with Brussels, Rwandan President Paul Kagame vowed that his country would "stand up" to Belgium.

"We would ask [Belgium]: 'Who are you by the way? Who put you in charge of us?' Rwandans believe in God, but did God really put these people in charge of Rwanda?" Kagame asked in an address on Sunday.

Since the beginning of the year, around 7,000 people have been killed in fighting between the M23 and DR Congo's armed forces in the east of the country, the Congolese authorities have said.

More than 850,000 people have been forced to flee their homes since the conflict increased in intensity in January, the UN children's agency, Unicef, said.

The M23 has taken control of two key cities - Goma and Bukavu - in the past two months.

On Monday, the EU sanctioned three of Rwanda's military commanders, citing connections to the M23.

The sanctions, which include the freezing of assets, were also applied to the head of Rwanda's state mining agency. The EU has accused the agency of exploiting DR Congo's conflict in order to extract valuable resources from the mineral-rich east.

Britain and Germany have also taken measures against Rwanda - over the past month both countries cut some of their aid to Kigali.

And in February, the UN Security Council demanded that the M23 end hostilities and that Rwanda should pull its troops out of DR Congo.

Rwanda's diplomatic spat with Belgium came a day before the Congolese government and M23 rebels were set to meet for peace talks.

But the rebels announced on Monday afternoon that they would no longer participate accusing unspecified international institutions of undermining the peace efforts.