At least three Afghan soldiers were killed in a suicide bomb attack Monday morning on an army minibus near their base in northern Balkh province, an official said. The suicide bomber was on foot and targeted the army vehicle in the Dahdadi district, said Munir Ahmad Farhad, spokesman for the provincial governor in Balkh. He said another 18 military personnel were wounded in the attack. Taliban spokesman Zabihullah Mujahid claimed responsibility for the attack in an email to media. Taliban insurgents have intensified their attacks across the country against Afghan security forces in the year since the international combat mission wound down. In eastern province of Nangarhar, a presidential palace guard was killed by unknown gunmen, said Attaullah Khogyani, spokesman for the provincial governor. Khogyani added that the man was shot inside his house and his mother was also wounded in the attack. "An investigation is underway by police to find out who is behind this attack," Khogyani said. The chaos of Afghanistan's war, now in its 15th year, often masks criminal behavior and personal feuds. In further violence Monday, an explosion tore through a market in the Yayakhil district of the eastern province of Paktika, Governor Aminullah Shariq said. Five civilians were killed and another nine wounded, Shariq said.