Burundi's ruling CNDD-FDD party and opposition groups met in the capital Bujumbura on Wednesday for mediated talks launched by Ugandan President Yoweri Museveni.

"I urge the people of Burundi to forget their past sectarian political differences and build their country on unity," Museveni said via Twitter.

He left Burundi on Wednesday without reaching a deal, after being appointed mediator by the five- nation East African Community (EAC) last week.

"The ruling party in Burundi and the opposition parties and the civil society have agreed to negotiate expeditiously, intensively, in order to reach an agreement," Museveni told reporters as he departed.

The task of mediating is now in the hands of Uganda's defense minister Crispus Kiyonga.

Burundi was plunged into crisis in April 2015 when President Pierre Nkurunziza announced he was running for a third term, which his opponents say violates the constitution and a peace deal. At least a hundred people have been killed in the subsequent months of protest and close to 60,000 refugees have fled to neighboring countries.

Government of national unity

Both opposition groups and the ruling party have said their positions will not change. The opposition said they would reject proposals for a government of national unity.

"A government of national unity cannot be based on legislative elections we have opposed," said Charles Nditije from the Amizero y'abarundi opposition coalition.

He was referring to the parliamentary elections on June 29 which the opposition boycotted and which were condemned internationally.

The opposition also intends to boycott the presidential poll.

Nditije said Museveni should demand that Nkurunziza adhere to the two term limit set out in the Arusha peace accords that ended the civil war in Burundi in 2005.

UN mediators have failed to resolve the conflict.

Museveni 's mediating initiative is also under pressure as time is running out. The presidential elections at the center of the dispute are now just six days away. They were to have been held on Wednesday (15.07.2015), but were postponed amid international pressure.

Armed oppostion

However, a group of 17 aid agencies and rights groups warned that the postponement "was an insufficient gesture that ignores the risk that the elections could spark major violence."

"Scores have already been killed, but this could just be the beginning of something much worse," said Ndung'u Wainaina from the Kenya-based International Center for Policy and Conflict.

Yolande Bouka, analyst at the Institute for Security Studies in Nairobi, told DW's AfricaLink radio show that while the political opposition was still trying to find its way to a political solution "there is now an armed opposition that has claimed grenade attacks and attacks on July 10 by assailants in the northern parts of the country."

Bouka also said that if President Nkrurunziza does succeed in getting his third mandate, "it is likely that this armed rebellion - though relatively small - may continue to destabilize the country."

Museveni, who has ruled Uganda since 1986, has himself scrapped presidential term limits, prompting some analysts to question his authority as a mediator.

"Museveni's own disregard for such limits makes him utterly unsuitable," said Chris McKeon, Africa analyst at Verisk Maplecroft.