Amnesty International on Thursday accused the Saudi-led Arab coalition battling rebels in Yemen of using banned cluster munitions in raids on residential areas.
The Brazilian-manufactured munitions were fired in a February 15 attack on three residential districts and agricultural land in Saada province of northern Yemen, a stronghold of the Shiite Huthi rebels, it said in a statement.
Two people were wounded in the attack, said Amnesty, which has also reported that the coalition used cluster munitions in October 2015 and May of last year.
The coalition "absurdly justifies its use of cluster munitions by claiming it is in line with international law, despite concrete evidence of the human cost to civilians caught up in the conflict", said Lynn Maalouf, research director at Amnesty's Beirut regional office.
"Cluster munitions are inherently indiscriminate weapons that inflict unimaginable harm on civilian lives," she said.
Amnesty called for Brazil "to join the Convention on Cluster Munitions and for Saudi Arabia and coalition members to stop all use of cluster munition".
Separately, Human Rights Watch in December accused the coalition of firing Brazilian-made rockets containing the outlawed munitions near two schools in Saada, killing two civilians and wounding six including a child.
The December 6 came a day after Saudi Arabia joined the US and Brazil in abstaining from a UN General Assembly vote that overwhelmingly endorsed an international ban on cluster bomb use.
The weapons can contain dozens of smaller bomblets that disperse over large areas, often continuing to kill and maim civilians long after they are dropped.
The Saudi-led coalition, which has come under repeated criticism over civilian casualties in Yemen, acknowledged in December it had made "limited use" of British-made cluster bombs but said it had stopped using them.
The conflict in Yemen has left more than 7,400 dead and 40,000 wounded since the coalition intervened on the government's side in March 2015, according to the UN.