The Pakistan-based extremists have also revealed that they plan to launch many more such attacks in the furture.
On a telephonic conversation with a news agency, Taliban spokesman Azam Tariq confirmed that his group was behind the strike.
"We proudly claim the responsibility for the suicide attack at the UN office in Islamabad. We will send more bombers for such attacks," he said.
The suicide blast at the UN food agency's fortified building killed as many as five people. Threatened by the terror strike, the UN temporarily closed its offices in Pakistan.
Apart from this, the attack also exposed the vulnerability of international agencies which are operating in the country to help thousands of civilians hurt and displaced due in the fight between the government and militant groups.