A powerful truck bomb went off in Kabul early on Friday, killing eight people and injuring 400 others in the first major attack in the Afghan capital since the announcement of the death of Taliban supreme leader Mullah Omar.
No group claimed responsibility for the attack, which came as the Taliban stepped up their summer offensive despite a bitter power transition within the militant movement.
The blast occurred in the Shah Shaheed residential area just after 1am and most of the casualties are believed to be civilians.
Public health ministry spokesperson Wahidullah Mayar said eight people died and 400 civilians were injured. He said 27 women and 10 children were among the injured and the toll could rise.
The massive blast rattled homes across the city, damaging buildings and shattering windows. Hospitals in Kabul were inundated with victims, Mayar said.
Kabul police chief General Abdul Rahman Rahimi said officials were looking to recover anyone trapped under the debris of damaged concrete structures.
"A truck packed with explosives was detonated in the crowded residential neighbourhood of Shah Shaheed (in east Kabul). Several houses in the area are badly damaged," he said.
"The killed and wounded include women and children, and labourers of a nearby marble stone company are among the victims. The attack was intended to cause mass murder."
It was not clear whether the real target was an Afghan National Army base close to Shah Shaheed. The Afghan security forces confirmed some personnel were injured but did not give details.
Mayar said there were reports of blood shortages in hospitals and urgent appeals for donors were circulating on social media.
The carnage came a day after Taliban insurgents killed nine people in multiple attacks on police targets in southern and eastern Afghanistan.
The attacks highlight growing insecurity amid a faltering peace process with the Taliban as Afghan forces face their first summer fighting season without full Nato support.
At least 8 dead, over 400 injured in Kabul blast
Surging civilian casualties
Civilian casualties in Afghanistan hit a record high in the first half of 2015, a UN report said on Wednesday, as Afghan forces struggle to contain the expanding conflict seven months after the Nato combat mission ended.
The report said 1,592 civilians were killed, a 6% fall from last year, but the number of injured jumped 4% to 3,329. Overall, casualties reached their highest level since the UN began issuing its authoritative reports in 2009.
The statistics are a grim indicator of the rising violence as the Taliban insurgency spreads north from its traditional southern and eastern strongholds, with Afghan forces increasingly battling the militants on their own.
US-led Nato forces ended their combat mission in Afghanistan last December, but a 13,000-strong residual force remains for training and counter-terrorism operations.
The Taliban face growing internal divisions after Mullah Akhtar Mansour was announced as the new head of the insurgent movement on Friday, following their confirmation of the death of Mullah Omar who led the militant movement for some 20 years.
An increasingly bitter power struggle has broken out, casting a pall over a fragile peace process aimed at ending Afghanistan's long war.
The Taliban distanced themselves from the second round of talks that were scheduled for last Friday but were cancelled after the announcement of Omar's death.
The powerful army chief of Pakistan, the Taliban's historic sponsors, said this week that ongoing efforts at talks are the "only credible way" to achieve lasting peace in the region.