An attack on a security post in Afghanistan's capital Kabul on Tuesday claimed four lives, including those of three attackers, police said."A terrorist equipped with a suicide vest blew himself up next to an office of the National Directorate for Security (NDS) killing himself and a guard, enabling two others to enter the compound but those inside returned fire and killed both within minutes," Kabul Police chief Abdul Rahman Rahimi told reporters at the site of the incident.The attack took place at around 1.40 p.m. in the 8th police district of Kabul city, Xinhua news agency reported.This is the second attack by militants in the same locality in Kabul city on Tuesday.In the first attack, a suicide bomber detonated his explosives-laden car against a foreign convoy injuring at least two people, including a foreigner.