Burundi's parliamentary polls scheduled for Friday will be postponed until a new date is set by the electoral commission, an aide to the president said, with the country rocked by weeks of political crisis.

"It is sure. There will be no elections on Friday," Willy Nyamitwe told AFP on Wednesday.

The announcement came as opposition parties said they were ready to resume talks to find a solution to the political crisis triggered by President Pierre Nkurunziza's controversial bid for a third term in office.

More than 30 people have died in protests that began when Nkurunziza announced in late April that he would stand for re-election after Burundi's constitutional court gave him the green light.

Opponents say his candidacy is unconstitutional and goes against the 2006 Arusha peace deal that ended 13 years of civil war.

Nkurunziza survived a coup attempt last month and has since ignored international pressure, including aid cuts, aimed at forcing him to withdraw or at least delay this month's parliamentary and presidential polls.

The electoral commission had been considering Wednesday whether to hold the parliamentary elections on June 5 as scheduled. The presidential election is still set for June 26.

In Musaga, a district in Burundi's capital that has been at the heart of the violent protests, there had been little enthusiasm and much trepidation in the run-up to Friday's polls.

With independent media silenced during the fighting sparked by the May 13 coup attempt, many people had not even been informed that voter cards were being handed out.

Nyamitwe said the new timetable for the parliamentary polls would take into account recommendations from regional leaders as well as constitutional limits.

Regional heads of state held a crisis summit at the weekend and urged a delay to the presidential vote until at least mid-July.

- 'People are tired' -

A group of 17 political parties and organisations issued a joint statement earlier Wednesday reaffirming their "commitment to continued dialogue" aimed at ensuring "free, calm, transparent and credible elections".

"For us the issue of Nkurunziza's third term remains non-negotiable, but as regional heads of state have formulated a framework for dialogue, we are ready to discuss this issue around the table," said Charles Nditije of the UPRONA party.

"There is no taboo issue," he said, adding that protests should continue in the meantime.

Sporadic unrest continued Wednesday. At least one man was killed in a grenade attack during a night of sporadic gunshots after which security forces were deployed Wednesday throughout the capital Bujumbura, which has seen more than a month of anti-Nkurunziza protests.

A rare anti-Nkurunziza protest was also held outside the capital. Thousands of people, displaced since the end of civil war, demonstrated in the president's home province of Ngozi, in the north of the country.

But in Bujumbura police were out in force to block attempts by protesters to take to the streets, witnesses said.

The slightest hint of a group gathering was met with automatic weapons fire and the use of tear gas, AFP correspondents said, and there were signs the daily demonstrations were beginning to fizzle out.

"If the number of demonstrators is falling, it's because a lot of them are in prison, injured, dead or terrified," said Jean-Marie, an unemployed driver in Musaga district, one of the areas of the capital that has been at the heart of the protest movement.

"People are tired," added Anatole, another resident of the district. "It's been a month since anyone went to work, they have nothing more to eat, and there are bullets whizzing by."

A senior police official said the intensified crackdown appeared to be working.

"We've adapted, and now we are out around the clock and we stop any gathering," he said, asking not to be named.