Burundi's main opposition leader has said he will participate in next month's presidential election if certain conditions are met.
"Armed youths must be disarmed and independent media be restored," Agathon Rwasa told BBC Great Lakes service.
Earlier, a group of 17 smaller opposition parties agreed to boycott the polls.
They say President Pierre Nkurunziza should not be allowed to seek a third term in office.
Burundi has been hit by street protests and a failed coup since President Nkurunziza announced in April that he would seek re-election.
On Thursday, UN envoy Said Djinnit, who had been hosting talks between the two sides stepped down, as the opposition had demanded.
Mr Rwasa said the current crisis should be resolved first to avoid "an election that may not meet all the democratic credentials".
"But we are ready to take part if the atmosphere is conducive and the electoral commission is well prepared," he said.
The presidential election was postponed by the electoral commission by 18 days, which falls short of a call by regional leaders to delay the poll by at least six weeks.
In a statement earlier on Friday, the 17 opposition parties demanded a further delay and noted that the electoral commission was not complete after two of its five members fled the country.
The crisis in Burundi is one of the issues expected to dominate proceedings at this weekend's African Union summit in Johannesburg, South Africa.
The opposition and civil societies say Mr Nkurunziza's attempt to run for office again contravenes the constitution, which states a president can only serve two terms.
However, the Constitutional Court has ruled that he was first elected in 2005 by parliament, not in a popular vote, and so he is eligible to stand again.