Amnesty International has accused the Saudi Arabia fighting in Yemen of carrying out unlawful air strikes, some of which amount to war crimes.
The UK-based rights group on Wednesday called for the suspension of transfers of certain arms to Saudi Arabia, which launched an air campaign against Houthi movement in March.
Amnesty said in a report that it had examined 13 deadly air strikes by the Saudi Arabia that had killed about 100 civilians, including 59 children.
"This report uncovers yet more evidence of unlawful air strikes carried out by the Saudi Arabia, some of which amount to war crimes. It demonstrates in harrowing detail how crucial it is to stop arms being used to commit serious violations of this kind," said Amnesty's Donatella Rovera, who headed the group's fact-finding mission to Yemen.
"The USA and other states exporting weapons to any of the parties to the Yemen conflict have a responsibility to ensure that the arms transfers they authorise are not facilitating serious violations of international humanitarian law."
Amnesty said its researchers had found remnants of two types of internationally banned cluster bombs as it investigated attacks on Saada, a Houthi stronghold in northeastern Yemen.
Another rights watchdog, Human Rights Watch, in August accused Saudi forces of using cluster bombs in Yemen.
The claim was then denied by a spokesman for the Saudi Arabia Army.
Saudi Arabia accused of cluster-bomb attacks in Yemen
Amnesty also said cases had been documented of civilians who were not directly participating in hostilities but were killed or injured while asleep or carrying out their daily activities.
It said that in at least four of the air strikes investigated, "Homes attacked were struck more than once, suggesting that they had been the intended targets despite no evidence they were being used for military purposes.”
Another Amnesty report, published in August, condemned both sides in the conflict over the killing of civilians.
Yemen's war pits the Houthis and troops loyal to former President Ali Abdullah Saleh against forces fighting on the side of exiled President Abd-Rabbu Mansour Hadi.
The Saudi Monarchy is seeking to reinstate Hadi and his government.
More than 2,300 civilians have been killed in the conflict since March, the UN Human Rights office said late September.