At least 80 people have been killed in two suicide bombings at a march in the Afghan capital Kabul, officials say.

More than 230 people have been injured in the attack, according to the interior ministry, and are being taken to Istiqlal hospital.

Witnesses said the blasts happened where hundreds of Afghanistan's Hazara minority had gathered to protest over the route of a planned multi-million dollar power line.

They were demanding a major electric transmission line pass through their impoverished areas, an option the government says would cost millions and delay the badly needed project by years.

One of the march organisers, Laila Mohammadi, said she arrived at the scene soon after the blast and saw "many dead and wounded people".


Image: Demonstrators were targeted during a protest over a planned power line

Islamic State has claimed responsibility for the attack.

Violence had been feared at what was the second march over the power line issue.

The demonstrators had been shouting "death to discrimination" and "all Afghans are equal".

The last protest in May attracted thousands of people and shut down the central business district.

The so-called TUTAP line is backed by the Asian Development Bank with involvement of Turkmenistan, Uzbekistan, Tajikistan, Afghanistan and Pakistan.

Image: Riot police stand guard during the demonstration

The original plan routed the line through Bamiyan province, in the central highlands, where most of the country's Hazaras live.

That route was changed in 2013 by the previous Afghan government.

Leaders of the marches have said the rerouting was evidence of bias against the Hazara community.

Hazaras are considered the poorest of the country's ethnic groups, and often complain of discrimination.

Less than 40% of the population in Afghanistan are connected to the national grid, according to the World Bank, with almost 75% of electricity imported.