Gunmen storm Save the Children office in Afghanistan

Earlier reports from a government official said there had been a suicide attack just outside the office in the city of Jalalabad in Nangarhar province, injuring 12 people.

"I hope for a quick and safe end to this horrific incident", he said on Twitter.

Afghan TV news channels showed a thick plume of black smoke rising above the compound and what appears to be at least one vehicle on fire outside the office.

"I am hearing gunfire from inside Save the Children compound".

Another witness told AFP: "It might be a complex attack". An explosion outside Save the Children's office in the city was followed by a lengthy siege.

No group had claimed responsibility for the attack, and the Taliban issued a statement denying that they were involved.

He said he had no word on casualties but a clash was going on at the scene.

Unofficial sources said eight people have been killed.

"Attacks directed at civilians or aid organisations are clear violations of global humanitarian law and may amount to war crimes", it said.

The province has become a stronghold for Islamic State, which has grown to become one of Afghanistan's most unsafe militant groups since it appeared around the beginning of 2015.

Security forces have cordoned off the area, not allowing journalists to get access to the site of the attack.

The attack is also the latest violence to strike a foreign aid group in war-torn Afghanistan.

The charity has been working in Afghanistan for more than 40 years, providing support to over 700,000 children.

Backed by intensive US air strikes, Afghan forces have claimed growing success against the Taliban and other militant groups, including Islamic State, but militant attacks on civilian targets have continued, causing heavy casualties.

  • Jon Douglas