BAQUBA, Iraq (AFP) - A woman bomber blew herself up outside a courthouse north of the Iraqi capital, killing nine people and wounding 21 in the worst Al-Qaeda-style suicide bombing by a female in three weeks. Two Iraqi army majors were among five soldiers killed while a policeman also died in the attack in the heart of Baquba, the capital of the restive province of Diyala, a security official said. The director of the main regional hospital, Ahmed Fuad, said a total of 21 people were being treated for injuries, including a woman and a child, and that nine people were killed. The attack occurred in front of the city courthouse, some 60 kilometres (37 miles) north of Baghdad. Lawyer Mohammed Timimi said a woman dressed in traditional Arabic dress that covered her from head to toe, carried out the attack. "I was going out to get photocopies. I saw a woman dressed in an abaya. As I stepped out she blew herself up," Timimi said. "There was a police car and soldiers in the compound at the time." Wednesday's attack was the worst suicide bombing in three weeks in Diyala. On September 15, a woman blew herself up in a crowd of people during a feast, killing 22 people and wounding 34. Diyala is one of the most dangerous places in Iraq. Insurgent groups and Al-Qaeda have continued launching attacks there despite a massive crackdown by US and Iraqi forces. A number of attacks in Diyala, especially suicide bombings, have been carried out by women. According to Iraqi security officials, more than 30 women have blown themselves up in Iraq this year compared to only eight last year. Wednesday's bombing came a day after Iraqi forces arrested a woman suspected of heading up the recruitment of female suicide bombers in Baquba.