At least eight United Nations staff-members and four protesters have been killed during protests in Afghanistan related to a purported burning of a Holy Quran, according to Afghan officials.

The killings occurred at an UN operational centre in the city of Mazar-i-Sharif in the northern part of the country after demonstrations over the burning of the Islam holy book by a U.S. preacher turned violent.

According to Al Jazeera, The Taliban has taken responsibility for the killings, warnings that it is part of its campaign against the upcoming presidential elections.

The UN indicated that four Nepalese Gurkha soldiers who worked as security guards at the center were among the casualties. According to unconfirmed reports two of the UN staff were beheaded.

An evangelical pastor in Florida reportedly burned a Quran earlier this month.

According to media reports, protesters stormed into the UN office, fired on guards, and lit fires inside the compound

Kieran Dwyer, director of communications for the UN mission in Afghanistan, told BBC the UN workers were trapped inside the compound and hunted down in what was an overwhelming situation.

These are civilian people, unarmed, here to do human rights work, to work for peace in Afghanistan - they were not prepared for this situation, he told the BBC.

An estimated 20 protesters were also wounded during the melee.

It is believed to be the worst attack against UN representatives in Afghanistan since 2001.

Ata Mohammad Noor, the governor of Northern Balkh province, told media that insurgents likely used the protests as cover to attack UN representatives.

The insurgents have taken advantage of the situation to attack the UN compound, he said.

According to BBC, the city is now under control and several people have been arrested.
 However, a state of emergency has also been declared in the city – with all roads in and out of blocked and cars are being checked.

UN secretary-general Ban Ki-moon expressed his outrage over the killings.

“This was an outrageous and cowardly attack against UN staff, which cannot be justified under any circumstances and I condemn it in the strongest possible terms,” Ban told reporters in Nairobi, Kenya, where he is making an official visit.

“I extend my condolences to those killed or wounded and their families.”

US President Barack Obama also condemned the attack in the strongest possible terms, adding that the UN’s work is essential to building a stronger Afghanistan.