Kabul, Jan 24 (IANS): At least two persons were killed and 12 injured in an attack on the headquarters of an international aid agency in Afghanistan's Jalalabad city on Wednesday, a government official said.

The attack, still ongoing, began at 9 a.m. when the attackers detonated explosives before storming the offices of the Save the Children aid agency in the eastern Afghan city.

According to the BBC, the assault began with a suspected suicide car bomb blast at the entrance of the agency's compound. Officials said about 50 staff were in the building at the time.

At least three gunmen are involved in the attack, reports said, with fighting continuing on the upper floor of the building.

Nangarhar provincial government spokesman Attaullah Khoghyani said one security force member and one civilian were killed, Tolo News reported.

Images showed a huge plume of thick black smoke rising from the compound and people fleeing from the area. The area was cordoned off by security forces. No group has yet claimed responsibility for the attack.

The aid agency tweeted that it was "devastated". "Our primary concern is for the safety and security of our staff."

Afghanistan's CEO Abdullah Abdullah said "such attacks show insurgents do not care and just want to create terror among the people".

All security forces across the country were ordered to "not show sympathy to insurgents and to eliminate them", Abdullah said.

Swedish Ambassador to Afghanistan Tobias Thyberg also condemned the attack. "We pay tribute to those who saved innocent lives and express our deep sorrow for the dead, the wounded and their families. This mad violence will not break Afghanistan."

There are several other aid agencies in the area along with government offices.

Save the Children carries out education, healthcare and protection work for children in Afghanistan.

Charity groups continue to work under tough conditions in Afghanistan, facing regular attacks and kidnappings.

In October last year, the International Committee of the Red Cross announced it would be "drastically" reducing "its presence and activities" in the country after several attacks and the killings of seven of its staff members.