In its World Report 2018, which reviews human rights practices in more than 90 countries, the rights group reported it had documented 87 unlawful attacks by the Saudi-led coalition fighting in Yemen.
Saudi Arabia said Wednesday it had intercepted a fresh missile attack by Yemeni rebels on the south of the kingdom and renewed its accusations that arch-foe Iran had armed them.
Yemen's rebels have threatened to block traffic across the Red Sea unless a blockade by a regional military alliance is lifted, prompting fresh accusations Tuesday of "terrorism" by their rivals.
The Houthi rebels, locked in a war against Yemen's Saudi-backed government, said they had fired a missile at the kingdom's southwestern province of Najran in a statement tweeted by their Al-Masirah television channel.
Sixty-eight Yemeni civilians were killed in two separate air raids by the Saudi-led Arab coalition in one day, the UN humanitarian Coordinator in Yemen Jamie McGoldrick said on Thursday.
Saudi-led air strikes killed 14 civilians in a village market near Yemen's battleground third city Taez as a nearly three-year bombing campaign intensified, an official and medics said on Wednesday.
Yemen's cholera epidemic has reached one million suspected cases, the International Committee of the Red Cross said on Thursday, with war leaving more than 80 percent of the population short of food, fuel, clean water and access to healthcare.