NAIROBI - At least 48 Kenyans were hacked or burnt to death in ethnic clashes between two rival groups, the worst single attack since deadly post-election violence four years ago, police said Wednesday. “It is a very bad incident.... They include 31 women, 11 children and six men,” regional deputy police chief Joseph Kitur said of the attack, which took place late Tuesday between the Pokomo and Orma peoples in the rural Tana River district. Kitur said “34 were hacked to death and 14 others were burnt to death,” while several huts were torched after a gang of men launched the attack, the latest in a long history of bitter clashes between the rival groups in the remote area of Kenya.