KUNDUZ (Reuters) - Three suicide bombers attacked a guesthouse used by foreigners in the northern Afghan province of Kunduz on Tuesday, killing four Afghan security guards employed by a German company, a senior police detective said. The raid came on the second day of the fasting month of Ramazan and 13 months after Taliban suicide bombers and gunmen stormed a US contracting company office in Kunduz, killing five, including three foreigners. One attacker detonated a car bomb at the gates of the guesthouse. The other two stormed the building where they fought Afghan forces for a couple of hours before detonating their explosives, said Kunduz police detective Abdul Rahman. Ten people, including civilians and a police officer, were wounded in the early morning attack, said Rahman. No foreigners were among the wounded, he said. The Taliban claimed responsibility for the attack, said spokesman Zabihullah Mujahid. The attack came as the US military has speculated whether Taliban leaders would take a break during Ramazan and cross over the border into Pakistan. Rahman said the slain Afghan security guards worked for a local security company, which was employed by German development agency GIZ, formerly called GTZ. The guesthouse was run by the local security company and sometimes accommodated foreign staff, he said. According to our knowledge it wasnt an attack against GIZ, it appears to be an attack against the local security firm, said Hans Spehling, a spokesman for GIZ, adding that all GIZ employees were safe. He also confirmed the local security firm was employed by GIZ.