Authorities in Afghanistan are struggling to figure out who's responsible for a suicide bombing that killed at least 55 people, mostly religious scholars, on Tuesday (November 20).

The Taliban has denied any responsibility for the attack that targeted a gathering of religious delegates from around Afghanistan They'd gathered to celebrate the birthday of the Prophet Mohammad.

And on Wednesday (November 21) the event's organisers condemned the bloody attack.

(SOUNDBITE) (Dari) ORGANIZER OF THE CEREMONY TO CELEBRATE THE BIRTH ANNIVERSARY OF PROPHET MOHAMMAD, SAYED SALAHUDDIN, SAYING: "Nobody ever heard of any attack on the anniversary of the Prophet Mohammad's birth.

That is an inhuman act".

Afghan officials said investigations into the attack were at an early stage.

But on Wednesday speculation on a motive was rife in the capital.

The aim could have been to undermine the government of President Ashraf Ghani, or to put pressure on the government's western allies as they pursue talks with the Taliban.

But without knowing who blew up the gathering of Sunni scholars, any theories on what motivated it were also simply guesses.

While both main militant groups in the country - the Taliban and Islamic State - are also Sunni, they have targeted religious scholar before... who've been aligned with the central government.

Last week, Taliban leaders met a U.S. special envoy in Qatar an attempt to pave the way for official peace talks to end the country's 17 year war.

It's the second meeting between the two parties in the past month and the U.S. envoy has now set a deadline of April 20 to end the war.

Hospital officials in Kabul said the toll from Tuesday's attack could rise as most of those wounded in the bombing had suffered severe injuries.