Clashes between the only rebel group in Burundi still fighting the government and forces loyal to the government intensified this week around the capital Bujumbura, reports said.

Rebels of the National Liberation Forces (FNL) have on several occasions during the last few days clashed with members of a former rebel group which is now part of the national unity government, reported Burundis national press agency ABP.

According to the report, the FNL killed at least one member of the government forces.

In other clashes with the Burundian regular government forces, at least five FNL rebels were killed and three were injured, according to a report by the missionary news agency Misna.

On Thursday, the UN envoy to Burundi Carolyn McAskie urged all parties to "end the violence, to respect human and international law and to observe a truce in order to create the necessary conditions for a total cessation of hostilities and for the protection of civilians".

More than 300 000 people have died in Burundi since 1993, when rebels from the Hutu majority took up arms against the Tutsi-led government and army.

McAskie denounced what she said were summary executions, torture, sexual violence and arbitrary detentions by all sides in the war in Burundi.

She said atrocities had been committed with complete impunity and actors on all sides of the conflict had exploited people for political and military gain.

Last week, 31 political parties and former rebel groups met in South Africa in order to solve two major issues: the distribution of senior positions between the Hutu and Tutsi ethnic groups, and the electoral calendar.

The FNL, as the only group still fighting the government, did not attend.

Out of the multitude of parties and former rebels groups meeting in Pretoria, only 20 groups ended up signing a power sharing deal.

Ten Tutsi minority parties rejected it.

A summit planned for this week to ratify the deal has been postponed to early September.

The peace broker, South-African Deputy President Jacob Zuma, insist that it is still possible for a new constitution to come into force on November 1st this year, as planned. The constitution would be a crucial step for Burundi in its transition to democracy after a decade of war. – Sapa-dpa.