The rights group Human Rights Watch has accused border guards in Saudi Arabia of killing Ethiopian migrants who tried to cross over into the kingdom from Yemen.
The group said it got its information from eyewitness reports of attacks being carried out on the migrants by border troops.
It also examined images that appeared to show dead bodies and burial sites in areas where the migrants attempted to cross.
Human Rights Watch said government forces sometimes fired machine guns and launched bombs in their attacks.
The border attacks had led to the killings of hundreds of unarmed migrants – possibly thousands – in recent years, the group said in a new report released Monday.
The United Nations has already questioned Saudi Arabia about its troops opening fire on migrants along its southern border with war-torn Yemen.
A Saudi government official told The Associated Press the Human Rights Watch report was "unfounded" and not based on dependable information.
The official did not want to be identified and did not offer specific evidence of how the information was unfounded.
Yemen's Houthi rebels did not answer requests for comment.
The AP reports the rebels are thought to earn tens of thousands of dollars every week smuggling migrants over the border.
About 750,000 Ethiopians live in Saudi Arabia.
As many as 450,000 of them likely entered the kingdom without permission, the International Organization for Migration reported in 2022.
The two-year civil war in Ethiopia's northern Tigray area displaced tens of thousands of people.
Saudi Arabia has been cooperating with Ethiopia's government to send thousands of migrants back to Ethiopia as it struggles with youth unemployment at home.
Human Rights Watch said it spoke to 38 Ethiopian migrants and four relatives of people who attempted to cross the border between March 2022 and June 2023.
They said they saw Saudi guards shoot at migrants or launch explosives at groups.
The report said the group also examined over 350 videos and photographs posted to social media or gathered from other places between May 12, 2021, and July 18, 2023.
It also examined several hundred square kilometers of satellite imagery captured between February 2022 and July 2023.
"These show dead and wounded migrants on the trails, in camps and in medical facilities…" the report said.
Migrants from Ethiopia have found themselves detained, abused and even killed in Saudi Arabia and Yemen during the war.
But in recent months, U.N. officials have expressed concern about Saudi forces attacking migrants coming in from Yemen.
An Oct. 3, 2022, letter to the kingdom from the U.N. said its investigators had received concerning accusations "of cross-border artillery shelling and small arms fire, allegedly by Saudi security forces causing the deaths of up to 430 and injuring 650 migrants."
The U.N. letter states that if migrants are captured, they are reportedly often "subjected to torture by being lined up and shot through the side of the leg to see how far the bullet will go or asked if they prefer to be shot in the hand or the leg."
The letter added, "Survivors of such attacks reported having to 'play dead' for a period of time in order to escape."
A letter sent by Saudi Arabia's mission to the U.N. in Geneva in March strongly denied the kingdom carries out any "systematic" killings on the border.
Saudi Arabia also said the U.N. had provided "limited information" so it could not comment further on the allegations.
I'm Jill Robbins.