The attack was the deadliest in Kenya since the 1998 United States embassy bombings Attack , and is the second deadliest overall , with more casualties than the 2002 Mombasa attacks , the 2013 Westgate shopping mall attack , the 2014 Nairobi bus bombings , the 2014 Gikomba bombings , the 2014 Mpeketoni attacks and the 2014 Lamu attacks .