The European Union said in a statement on Wednesday that "we stand united with the people of Afghanistan" after the deadly attack in Jalalabad on Tuesday that killed 15 people including an IOM employee.
"In the wake of the attacks in Jalalabad, Afghanistan, which claimed the lives of 15 civilians, including three humanitarian workers from some of our partners, we stand united with the people of Afghanistan and with the whole humanitarian community," the EUís Commissioner for Humanitarian Aid and Crisis Management Christos Stylianides said in the statement.
"My thoughts are with the families of the victims and all those who were severely wounded as they tried to escape from the building under attack," he said.
"The senseless, pervasive violence in Afghanistan continues to pose a threat to the lives of innocent civilians and of those whose mission is to save the lives and relieve the suffering of vulnerable people.
"All parties to this conflict must abide by the principles of International Humanitarian Law, and respect and protect civilians and those who are assisting them," he added.
The statement was issued after insurgents carried out an attack that lasted over six hours on Tuesday.
Officials said a car bomb was detonated close to the entrance of the compound at about 11.30am and was followed by two gunmen storming the building.
A number of employees were able to escape during the course of the day, but many remained trapped inside.
Throughout the day gunfire could be heard coming from the area while plumes of black smoke could also be seen soon after the attack started.
This comes just three days after a complex attack on a midwife training center in Jalalabad.
This attack lasted almost six hours - and claimed the lives of two people.
On Monday Nangarhar provincial health officials raised concerns over the sharp increase in civilian deaths in the past three months in the province.
They said 160 people had been killed and over 490 wounded in the province in serious security incidents in this time.