A bomb failed to explode outside the international Red Cross office in Pakistan\'s largest city of Karachi on Saturday, police said. A small blast did take place from the detonator of the home-made bomb, which two motorcyclists left in a trash bin outside the main gate of the International Committee of the Red Cross office in Karachi\'s Bahadurabad area. \"A detonator of a locally-made bomb exploded, but it failed to explode the bomb,\" senior police investigator Omar Khitab told reporters. \"There were no casualties or damage,\" he added. Khitab said that the bomb resembled the one defused by police on Friday in the residential colony of Karachi\'s Jinnah Postgraduate Medical Centre. Provincial interior ministry spokesman Sharfuddin Memon confirmed the incident. No one has so far claimed responsibility for the botched attack. Karachi suffers from killings linked to political and ethnic tensions and crime, but Islamist militant violence is also on the rise in the city of 16 million people whose port is a hub for NATO supplies bound for Afghanistan. Last month, it took the navy 17 hours to fight off a handful of militants who killed 10 security officials and destroyed two US-made aircraft at the only naval air base in Karachi.