Rwanda says it is pulling out of a central African regional bloc after a diplomatic row over its involvement in the conflict in the east of the Democratic Republic of Congo.

The country was supposed to take up the chairman role of the Economic Community of Central African States (ECCAS), which rotates between its 11 members.

But it was prevented from doing so at a meeting on Saturday in Equatorial Guinea.

Announcing its decision to leave ECCAS, Rwanda said its right to take up the "chairmanship… was deliberately ignored in order to impose the DRC's diktat".

As a result, it saw "no justification for remaining in an organisation whose current functioning runs counter to its founding principles and intended purpose".

The row comes as efforts to end the fighting in eastern DR Congo continue. Following US mediation, Rwanda and DR Congo are working on a draft peace plan that is expected to be signed later this month.

According to a statement from the Congolese presidency, the ECCAS leaders at the summit "acknowledged the aggression against the Democratic Republic of Congo by Rwanda and ordered the aggressor country to withdraw its troops from Congolese soil".

It added that until the dispute was resolved, it was decided that Equatorial Guinea would remain in the chairman role "to the detriment of Rwanda".

In comments directed at Rwanda, Congolese government spokesman Patrick Muyaya said that "one cannot continually and voluntarily violate the principles that underpin our regional institutions and claim to want to preside over them".

He added that the ECCAS decision "should inspire other regional organisations to adopt a firmer stance against Rwanda".

Rwanda has been accused of supporting the M23 rebels in the east of the DR Congo. The group has made major advances at the beginning of the year, taking the key regional cities of Goma and Bukavu.

DR Congo's government, the US and France have identified Rwanda as backing the M23.

Last year, a UN experts' report said that up to 4,000 Rwandan troops were fighting alongside the rebels.

But Rwanda has denied the accusations, saying instead that its troops were deployed along its border to prevent the conflict spilling over into its territory.

Rwanda has once before, in 2007, left ECCAS, whose mission is to foster co-operation and strengthen regional integration in central Africa. It rejoined several years later.