MOGADISHU — At least two people were killed and seven wounded when a bomb ripped through a busy market in the Somali capital on Monday, a government official said. It is not clear who carried out the attack but in the past similar attacks in Mogadishu have been claimed by Al-Shabaab militants, who have vowed to wage a series of attacks during Ramadan, the Muslim fasting month which started on Sunday. Islamist al Shabaab gunmen shot dead three people on Sunday and said the killings were just the start of the group's Ramadan campaign. “It was a bomb they planted in a small room in the market that the local government staff used as they collected tax,” Ahmed Hassan, the district commissioner of Kaaraan district, told reporters. The government and African Union peacekeepers have stepped up security to try to prevent assaults during Ramadan by Al-Shabaab, which has waged a seven-year campaign to impose its strict interpretation of Islamic law. In the past year or so, Al-Shabaab has killed dozens of people in guerrilla-style assaults in Mogadishu, on UN offices, the presidential compound, Parliament, and the courts. — Reuters