At least six people were killed and 45 wounded in an attack at an intelligence agency headquarters in eastern Afghanistan early Saturday, Al Jazeera reported.

Zabihullah Mujahid, a Taliban spokesperson, claimed responsibility for the attack, Associated Press, or AP, reported.

The attack was carried out by two suicide car bombs outside the headquarters of the National Directorate of Security, or NDS, in Jalalabad, Ahmad Zia Abdulzai, spokesperson for the Nangarhar provincial governor, told Reuters.  This is the latest in a series of attacks targeting the Afghan intelligence apparatus. In December 2012, NDS head Asadullah Khalid was seriously wounded in an attack by Taliban.   

Abdulzai also added that four NDS officers and two civilians were killed when a truck and a smaller car, both loaded with explosives, attacked the compound and in an ensuing a gunfight between Afghan forces and the militants. However, it was not immediately clear how many attackers were involved and whether they were all killed.

Jalalabad, which is one of Afghanistan’s largest cities, is also located in one of the country’s most troubled regions. Earlier this year, at least 20 people were killed in two separate attacks on a police station and a provincial court building in the city. Afghan security officials have repeatedly accused Pakistan of providing support and sanctuary to militants that attack Afghanistan. Pakistan, however, has consistently denied the allegations.

As NATO troops have largely withdrawn from Afghanistan, this is the first year that Afghan security forces have operated on their own. In the recent months, attacks by Taliban have also intensified, posing a threat to the fragile Hamid Karzai-led government in Afghanistan.