Two attacks that struck Nairobi this week were inspired by, but not carried out by, al-Shabaab, a Nigerian government spokesman said. One person was killed and 20 others were injured in a series of grenade attacks in Nairobil. One struck a nightclub early Monday and another struck a bus station during rush hour. Alfred Mutua, a spokesman for the Kenyan government, told CNN International the attacks weren\'t the work of al-Shabaab. \"It was two young guys inspired by al-Shabaab,\" he said, \"but not directed by al-Shabaab leadership.\" Al-Shabaab said it could take on the Kenyan military when forces crossed the northern Kenyan border into Somalia in response to a spate of kidnappings in the region. U.S., French and British authorities had issued travel advisories about the region either before, or shortly after, Monday\'s attacks. One American, a Danish national and their Somali colleague, all working for the Danish Demining Group, were kidnapped in northern Somalia, The Wall Street Journal reported Wednesday. Last week, two Spanish aid workers with Doctors Without Borders were kidnapped from the region. A 66-year-old French woman died after she was taken hostage from the area in early October. Washington this week denied allegations the U.S. military had joined the Kenyan offensive.