Using hand grenades, automatic rifles and a suicide-bomber, the militants stormed 14 Riverside in Nairobi on Tuesday afternoon, a venue popular with business travelers and Kenya’s elites and home to offices of companies including Pernod Ricard SA and Dow Chemical East Africa Ltd. That precipitated an 18-hour siege around the DusitD2 hotel, which President Uhuru Kenyatta said ended about 9 a.m. Wednesday with the attackers dead. Somalia-based al-Shabaab took responsibility for the assault, the latest in a recent wave of jihadist strikes across Africa, including in Nigeria and Mali, which a loose coalition of African, Western and United Nation troops are struggling to stop. It’s al-Shabaab’s first significant assault in Kenya since it killed 147 people at a northeastern university in April 2015 and echoed a September 2013 attack on Nairobi’s Westgate mall that left 67 dead and rocked the tourism industry.