The Afghan minister for refugees Khalil Ur-Rahman Haqqani and two others was killed on Wednesday in a suicide explosion at the ministry's offices in the capital Kabul, a government source told AFP.

This is the most significant attack on a senior Taliban official since they returned to power three years ago.

The blast occurred within the ministry premises, resulting in the death of Khalil Haqqani. His final official photograph captured him attending a meeting led by deputy prime minister Mullah Abdul Ghani Baradar earlier that day.

Taliban security forces restricted access to the explosion site and prohibited photography.

"Unfortunately an explosion happened at the Ministry of Refugees and minister Khalil Ur-Rahman Haqqani has been martyred along with some of his colleagues," the official said, requesting not to be named.

He added that the explosion was caused by a suicide blast.

Khalil Ur-Rahman Haqqani was the brother of Jalaluddin Haqqani, who founded the Haqqani network. He was also the uncle of Sirajuddin Haqqani, the current interior minister.

Former president Hamid Karzai and the minister's nephew, Anas, expressed their deep condolences.

Pakistan's foreign minister Ishaq Dar denounced the incident as a "terrorist attack."

"Pakistan unequivocally condemns terrorism in all its forms and manifestations," Dar said, noting his government's communication with Kabul for additional information.

According to Michael Kugelman of the Wilson Center's South Asia Institute, Haqqani's death could be the most substantial setback for the Taliban since regaining power, considering his position and influence. This incident occurs whilst the Taliban attempts to establish legitimacy through maintaining peace after years of conflict.

The Haqqanis are said to be engaged in a struggle for influence within the Taliban authorities.

According to press reports, they are pitted as a pragmatic faction up against supporters of the severe interpretation of Islamic law in line with the Taliban's supreme leader based in Kandahar.

Several senior Taliban leaders have been killed since their return to power, including provincial governors, commanders and religious clerics, mostly in attacks claimed by the Islamic State group.

The regional chapter of Islamic State, known as Islamic State Khorasan, is active in Afghanistan and has regularly targeted civilians, foreigners and Taliban officials with gun and bomb attacks.