Kabul:- Multiple explosions rocked polling centres across Kabul on Saturday, as voters cast their ballots in long-delayed legislative electionsinfo-icon.

Voters were seen fleeing a school in the north of the Afghan capital after a blast, an AFP correspondent said, with witnesses reporting explosions at other polling centres.

A man told AFP that "he was trying to vote but then had to run for his life after the blast" at the school that had been turned into a polling centre.

He saw several casualties evacuated.

Interior ministry spokesman Nasrat Rahimi confirmed another two explosions near polling centres.

At least 30 people have been taken to a trauma hospital run by the Italian NGO Emergency, including a dead child, the organisation said on Twitterinfo-icon.

Afghan officials confirmed there have been casualties but would not provide a number. At least one official said there were "fatalities and injuries" from the explosions.

The blasts come after the Taliban warned voters to boycott the "sham and theatrical process to protect their lives".

Around 70,000 security forces have been deployed to protect polling centres across the warinfo-icon-torn country.

Afghans braced for more deadly violence as voting began in the long-delayed legislative election that the Taliban had vowed to attack.

Long process

After shambolic preparations, polling centres opened at 7am across war-torn Afghanistaninfo-icon, but threats of militant attacks and expectations for industrial-scale fraud are likely to deter many voters.

People queueing outside a polling centre in Kabul complained the process was taking too long, apparently due to hiccups with biometric voter verification devices that are being used in the election for the first time.

"I came here early to finish and go home quickly, but we have been waiting for an hour and they have not started yet," Mustafa, 42, told AFP.

"The queue is getting longer. They have to register our votes quickly -- we are afraid a bomber or a blast may hit usinfo-icon."

Chief Executive Abdullah Abdullah, Afghanistan's equivalent of prime minister, also waited for more than half an hour at a polling centre in the Afghan capital as election workers searched for his name on a voter registration list, a live broadcast on Tolo News showed.

Almost nine million people registered to vote in the parliamentary election, which is more than three years late and only the third since the fall of the Taliban in 2001.

In the days leading up to the poll, the Taliban issued several statements urging candidates to withdraw and voters to boycott what the group calls a "malicious American conspiracy".

The killing of a powerful police chief in a highly secure compound in the southern province of Kandahar on Thursday eroded confidence in the ability of security forces to protect voting locations.

Voting in Kandahar has been delayed by a week following the attack that killed three people, including General Abdul Raziq.

Despite the risks, President Ashraf Ghani urged "every Aghan, young and old, women and men" to exercise their right to vote, after casting his ballot in Kabul.

Dozens of men and women clutching their identification documents were seen lining up outside voting centres in the Afghan capital, as a heavy security presence blocked many streets.

A woman dressed in a burqa exiting a polling centre in the northern city of Mazar-i-Sharif told AFP she had been worried about "security incidents", but decided to vote anyway.

"We have to defy the violence," Hafiza, 57, said. "In previous years we were not happy with the elections, our votes were sold out."

The Independent Election Commission (IEC), which has been skewered over the chaotic lead-up to the ballot, on Friday urged Afghans to "vote only once" and called on others not to interfere in the process.

"They should observe impartiality in the election so that we have a transparent, impartial and fair election in Afghanistan," IEC chief Abdul Badi Sayyad told reporters.

Taliban threats

Preparations for the vote have been marred by a wave of poll-related violence that has left hundreds dead or wounded.

At least 10 candidates out of more than 2,500 contesting the lower-house election have been killed so far.

The most recent victim was Abdul Jabar Qahraman, who was killed on Wednesday by a bomb placed under his sofa in the southern province of Helmand.

Most of the candidates are political novices and include doctors, religious scholars and journalists. Those with the deepest pockets are expected to win.

The United Nationsinfo-icon Assistance Mission in Afghanistan, which has spearheaded international efforts to keep Afghan organisers on track, on Friday called on voters to "exercise their constitutional right to vote".

The poll is seen as a crucial test for next year's presidential election and an important milestone ahead of a UN meeting in Geneva in November where Afghanistan is under pressure to show progress on "democratic processes".

But there are concerns the results could be thrown into turmoil if the biometric verification devices are broken, lost or destroyed.

Votes cast without the controversial machines will not be counted, the IEC has said.