Fighting ongoing near site of US blast in Afghanistan: NATO

A video grab from April 13, 2017 footage courtesy of the Department of Defense shows a GBU-43/B Massive Ordnance Air Blast bomb striking an IS cave and tunnel systems in the Achin district of Afghanistan's Nangarhar province

Fighting was still ongoing Wednesday near the site in eastern Afghanistan where the US dropped a massive bomb on an Islamic State group stronghold six days ago, a NATO spokesman said.

Security forces have denied access to residents and media to the area where the US military dropped its GBU-43/B Massive Ordnance Air Blast, dubbed the "Mother of All Bombs" and used in combat for the first time on April 13.

The target was caves and hideouts being used by the jihadist group in the Achin district of Nangargar province.

The blast triggered shockwaves which residents said they felt miles away. The Afghan defence ministry has said it killed at least 95 militants, including some IS commanders and foreign fighters, but no civilians.

The statement could not be independently verified.

"We are still engaged in active combat with the enemy" in the area, Captain Bill Salvin, a spokesman for NATO's Resolute Support mission in Afghanistan told AFP late Wednesday.

Fighting was ongoing, he said, and there are a "lot of IEDs (improvised explosive devices)".

A spokesman for Afghan special forces said the presence of landmines and "pockets of resistance" on top of mountains had slowed down operations in the area. He did not specify if the fighters were Islamic State.

AFP correspondents said they saw no sign of fighting in the immediate area Wednesday, but were turned away by security forces before reaching the site.

Salvin refused to confirm or deny the toll given by Afghan authorities, but said NATO had a "very high confidence" there had been no civilian casualties, adding security forces had warned families 48 hours before the strike.

An assessment of the area could be "going on for a while", he added.

Ahmad Jan, a resident of Achin who fled IS fighting and moved with his family to the provincial capital Jalalabad before the bomb was dropped, told AFP he had no idea whether his house or relatives survived the attack.

"No one can go there, they have completely blocked the area. I don't know if my house is destroyed. They have not even shown any dead bodies to anyone," he said.

Some Afghans have condemned the use of their country as what they called a testing ground for the weapon, and against a militant group that is not considered as big a threat as the resurgent Taliban.

Analyst and retired general Atiqullah Amarkhail told AFP the US military needed time to analyse the impact and clean the debris.

"It was not an ordinary bomb. It carried a special kind of explosives, it was tested in a mountainous area for the first time, I believe a team of US experts are now working on the ground to assess the effects and impacts," he said.

IS, notorious for its reign of terror in Syria and Iraq, has made inroads into Afghanistan in recent years, attracting disaffected members of the Pakistani and Afghan Taliban as well as Uzbek Islamists.

But the group has steadily lost ground in the face of heavy pressure both from US air strikes and a ground offensive led by Afghan forces.