Saudi-led coalition air strikes on a rebel stronghold in Yemen have destroyed houses, markets and a school, killing dozens of people in what could amount to war crimes, Human rights Watch said Tuesday. The US-based rights group said it had investigated the attacks on the **rthern city of Saada and found that at least 59 people had died in a month, from April 6 to May 11, including 14 women and 35 children. Attacks on houses alone have killed 51 people, all of them civilians, according to Human rights Watch, which dis*****ed two researchers to the city last month to interview witnesses.