Three suicide bombers attacked a police headquarters close to the Afghan capital Kabul on Friday killing a policeman and wounding six others, said officials. Provincial police Chief of Kabul, General Mohammad Zahir, said, "A suicide bomber driving a minivan detonated himself at the entrance gate of the Sarobi police headquarters." Deputy Minister of Interior General Ayub Salangi confirmed that the clash erupted in the morning, lasting two and a half hours. It ended with the killing of three attackers and injuring a number of police personnel, he added. The security officials said one of the assailants, who came in a van, blew himself up in front of the entrance to the district center and the rest started exchanging fire with the security personnel. Heavy contingents reached the scene to control the situation. Officials in the hospital confirmed receiving one dead and six wounded people from the scene of fighting. Sarobi, on the main road between Kabul and Jalalabad city, is a volatile district in a region seen as key to protecting the capital. Afghanistan is to face a major transition after Presidential elections on April 5, as some 55,000 US-led combat troops pull out of the country after 13 years of battling the Taliban insurgency.