At least seven people have been killed and 21 injured in a powerful explosion in central Kabul today. <br/><br/>The explosion ripped through Kabul's heavily-fortified diplomatic area of Wazir Akbar Khan. <br/><br/>A suicide bomber reportedly detonated his explosives in 14th Street in Wazir Akbar Khan – inside the Green Zone. <br/><br/>TOLO news journalists at the scene reported that they saw many casualties. <br/><br/>Security forces immediately cordoned off the area and ambulances were seen rushing casualties to nearby hospitals. <br/><br/>According to the Ministry of Defence, which has an office in 14th Street, the explosion happened close to their building but they said they are not the target. <br/><br/>The explosion happened at about 4 p m local time when many government officials and embassy staff were leaving the area for the day. <br/><br/>The suicide bomber reportedly entered the area through a park bordering the diplomatic zone and was able to penetrate the layers of security and gain access directly into the highly-fortified area that houses numerous embassies, some government offices, guest houses and a few private companies. <br/>