A suspected truck bomb has ripped through the heart of Kabul's diplomatic district, killing at least 80 people and wounding hundreds, in a powerful blast described by officials as "one of the biggest" to have hit the Afghan capital.

Sources said Wednesday's suicide attack took place near Zanbaq square, in Kabul's 10th district, close to shops and restaurants, as well as government offices and foreign embassies.

There was no immediate claim of responsibility. Zabihullah Mujahid, a spokesman for the Taliban, told Al Jazeera that the group was not involved in the attack.

Police and health officials confirmed to Al Jazeera that at least 80 people were killed and more than 300 wounded in the attack. The death toll was expected to rise.

The victims appear mainly to have been Afghan civilians and there were no immediate reports of casualties among foreign embassy staff.

"The area is heavily guarded and there is usually traffic jam, just because of security-controlled points in the area," Mushtaq Rahim, an independent analyst and security commentator, told Al Jazeera from Kabul.

"And that was one of the main reasons that we had so many civilian casualties, because of the congestion that happens in that area."

Video shot at the scene showed burning debris, crumbled walls and buildings and destroyed cars, many with dead or wounded people inside.

Al Jazeera's Qais Azimy, reporting from Kabul, said the location of the attack was very significant, as it hit one of the Afghan capital's busiest and most secure parts.

"Kabul has been very quiet for the past week but police has confirmed to us that this was one of the biggest blasts Kabul has ever seen," he said.

Azimy said police were investigating the possibility that the attacker had detonated a truck packed with explosives.

"If that is true, if a truck full of explosives could manage to get to that highly secure part of Kabul, then that is going to raise a lot of questions - not only among those diplomats living in the area, but also Kabul's regular residents."

Rahim, the security commentator, agreed, saying many in Kabul would be asking that question.

"Heavily-loaded vehicles are checked thoroughly and usually they are not allowed to pass through these areas without prior clearance from the security forces," he said.

"If it is not a heavy vehicle, smaller vehicles can pass through … security checks do happen but during the morning times due to so much rush it’s impossible to check every single vehicle that passes through the area."

ISIL has claimed responsibility for several recent bombings in the Afghan capital, including a powerful blast targeting an armored NATO convoy that killed at least eight people and wounded 28 on May 3.

Sigmar Gabriel, Germany's foreign minister, said that an Afghan security guard was killed and several employees of the German embassy wounded in the blast.

Sushma Swaraj, India's minister of external affairs, tweeted that all of the staff at the Indian embassy "were safe in the massive Kabul blast".

French officials said the country's embassy in Kabul was damaged in the attack, but there were no signs at this stage of any victims.

Ambulances rushed to the scene of the blast, while a huge plume of smoke could be seen rising from the area.

Houses and shops hundreds of meters away from the blast site were damaged, with windows and doors blown off their hinges.

"The explosion was so loud that it shattered all my windows, did not hear something this big before," Fatima Faizi, a Kabul resident, told Al Jazeera.

PHOTO CAPTION

Wounded men arrive at a hospital in Kabul after the blast

Al-Jazeera