Kabul: A militant attack on a provincial headquarters of the department of refugees and migrants on Tuesday left at least 18 people dead and 15 others injured, officials told the media.

A first suicide attacker detonated explosives he was carrying, allowing two other militants to enter the building in Jalalabad, capital of Nangarhar province, where they were barricaded for six hours until they were shot dead, Efe reported.

"Initial information shows a blast took place near to the Provincial Directorate of Refugees and Repatriation followed by gunshots shortly before 12:00pm in Jalalabad city's Police District 3," the provincial governor's spokesperson Ataullah Khogyanai said.

According to the spokesperson, the incident was a terrorist attack and security forces evacuated the director of the refugee department and many other employees.

The attack was carried out when a meeting was under way at the Refugee Directorate between officials from the institution and partner and donor organisations.

Nangarhar has witnessed a number of attacks this month.

On Saturday, a group of insurgents attacked a midwife training center in the province, killing at least five people, while on July 11 security forces killed two attackers who had laid siege to the department of education in Jalalabad and killed 11 employees.

On July 1, the city saw a suicide attack which killed 19 people, most of them members of the Hindu and Sikh minorities, coinciding with President Ashraf Ghani's visit to the city.