Men transport an injured person at a hospital after a suicide attack in Kabul, Afghanistan July 23, 2016. [Photo/Agencies]

KABUL -- At least 61 people were killed and 207 others wounded after a deadly blast hit a protest in Afghan capital of Kabul on Saturday, a health official said.

"The latest information found 61 people were killed and 207 wounded. As I provide these figures there is fear that the number of deaths and injuries may further go up because the casualties were shifted to multiple hospitals across the city," Dr. Ismahil Qawossi, a spokesman of Public Health Ministry, told Xinhua.

The incident took place at around mid-day when thousands of people were holding a demonstration to register their protest over change in route of a major electricity line.

The nature of the blast still remained unknown. However, unofficial sources said the explosion was conducted by a suicide bomber.

They said another bomber was shot dead by security forces before he detonated his explosive jacket.

The demonstration, held by the so-called "Enlightening Movement" protesters mainly from minority Hazaras, started on Saturday morning.

Media reports said the Islamic State (IS) claimed responsibility for the attack. The Taliban militants denied involvement in the deadly incident.

Local media footage showed hundreds of Afghans who stand in long queues outside hospitals to donate blood for the victims.

"Mohammad Ashraf Ghani, President of the Islamic Republic of Afghanistan is deeply grieved by the explosions among protestors today in Kabul. The President said that holding protests is the right of every citizen of Afghanistan and the government puts all efforts to provide security for the protestors, but terrorists entered the protests, and carried out explosions that martyred and wounded a number of citizens including members of security and defense forces," the Presidential Palace said in a statement.

The president ordered all government authorities and entities to utilize the available resources to reach to those injured in the explosions, and urgently take the wounded to well-equipped hospitals for treatment, the statement said.

The Afghan leader also offered his condolences and sympathies to the families and all those affected, said the statement.