A Saudi-UAE-led military coalition battling Yemen's Houthi rebels killed dozens of fishermen in bombing attacks on fishing boats last year, a leading rights group has said.
Human Rights Watch on Wednesday called for a United Nations investigation as it said that at least 47 Yemeni fishermen, including seven children, were killed in five attacks carried out by the coalition in 2018.
The New York-based group also said that more than 100 Yemeni fishermen are being held in Saudi Arabia, some of whom have been tortured in custody.
There was no immediate response by the coalition to the HRW allegations.
The rights group said it interviewed "survivors, witnesses, and knowledgeable sources about seven fishing boat attacks: six in 2018 and one in 2016." Civilians died in five attacks carried out by small arms and heavy weapons.
It said the fishermen waved white cloths, raised their hands, or otherwise showed they posed no threat. In three attacks, coalition forces did not attempt to rescue survivors adrift at sea, and many drowned, according to Human Rights Watch.
The group said the coalition officials who ordered or carried out the attacks or tortured detainees "are most likely responsible for war crimes".
"The naval attacks on Yemeni fishing boats make it clear that the Saudi-led coalition is not only killing civilians through countless illegal air strikes, but also while conducting operations at sea," said Priyanka Motaparthy, Human Rights Watch's acting emergencies director.
Human Rights Watch also said that the Houthi rebels - who control the capital, Sanaa, and other cities in northern Yemen - have also attacked commercial traffic in the Red Sea.
Speaking to Al Jazeera, Motaparthy said the coalition has repeatedly told the international community that it is improving its targeting practices to eliminate the possible loss of civilian lives.
"The attacks we documented are very dramatic examples of how that is not true," she said, speaking from New York.
"Coalition ships could see the fishermen they were attacking," she continued. "Nevertheless they went ahead with these attacks and that tells us there's very little cost for coalition forces to take civilian lives in Yemen."
US drone 'shot down'
The war in Yemen began in March 2015 when the Saudi-UAE-led coalition launched its air campaign to prevent the Houthis from overrunning the south and reinstate the internationally recognised government of President Abd-Rabbu Mansour Hadi.
The long-running conflict has escalated into what the UN has described as the world's worst humanitarian crisis, with more than two-thirds of the population in need of aid, millions of people forced from their homes, and tens of thousands killed.
In its report, Human Rights Watch called for the United States and other Western countries to "immediately cease all sales and transfers of weapons" to Saudi Arabia.
The call came as the Houthi rebels claimed on Wednesday they had shot down a US military drone in Yemen's north the previous day.
Yahia Sarie, a Houthi military spokesman, said in a statement their air defences downed a US MQ-9 drone over the northern city of Dhamar. He said the drone was hit by a missile.
"The rocket which hit it was developed locally and will be revealed soon at a press conference," Sarie wrote on Twitter. "Our skies are no longer open to violations as they once were and the coming days will see great surprises," he added.
The US military's Central Command said it was aware of claims that a US drone had been shot down over Yemen, but declined to elaborate.
A US official told Reuters news agency that it appeared that the military drone had been shot down by a surface-to-air missile operated by the Houthis. The official said that while losing a drone was expensive, it was not unprecedented and it was unlikely to lead to any major response by the US
In June, the US said an MQ-9 Reaper was shot down by the Houthis. It said Iran helped the Yemeni rebels bring down the drone.
US forces have occasionally launched drone and air raids against Yemen's al-Qaeda branch, known as Al Qaeda in the Arabian Peninsula (AQAP).
The group has taken advantage of the long-running conflict between the Houthis and government forces to try to strengthen its position in the impoverished country.
In recent weeks, a new front appeared in Yemen's multilayered conflict after fighting broke out in parts of the south between erstwhile allies in the fight against the Houthis.
Earlier this month, the UAE-trained Security Belt Forces, dominated by pro-secession Southern Transitional Council (STC) fighters, threw Hadi loyalists out of the southern port city of Aden, the temporary seat of Hadi's government.
The Yemeni government denounced the STC's seizure of Aden as an Emirati-backed "coup", and on Tuesday said the UAE was "fully responsible for the armed rebellion", urging it to stop backing "this militia".
"The armed rebellion ... is supported financially, logistically and with the knowledge of the UAE," Abdullah al-Saadi, Yemen's permanent representative at the UN, said.
But Saud al-Shamsi, the UAE's deputy permanent representative to the UN, rejected the accusations his country was supporting the separatist fighters.
"We regret hearing today allegations directed against the UAE regarding developments in Aden, which we categorically reject," he said.
He added his country is doing all it could to "de-escalate" the situation in Yemen.
On Tuesday night, STC chief Aidarus al-Zubaidi arrived in the Saudi city of Jeddah at the invitation of the kingdom's foreign ministry, for talks to resolve the standoff.
But Yemen's Deputy Foreign Minister Mohammad al-Hadhrami said on Twitter on Wednesday that the government "will not take part in discussions with the [STC] ... unless it withdraws from positions it has seized" and hands over all the weapons it captured from government troops.