Myanmar security forces shot dead at least six people in the troubled western state of Rakhine on Thursday, after soldiers and police detained hundreds of people at a school, a military spokesman said.
The soldiers had rounded up about 275 people during a search for members of the rebel Arakan Army, said brigadier general Zaw Min Tun from the military's True News Information Team.
There were conflicting accounts of events leading up to the shooting, which took place in an area off-limits to reporters and most aid agencies.
Zaw Min Tun said some of the detainees attempted to seize weapons in the early hours of the morning, forcing security forces to fire into a crowd.
"We warned them verbally. Then we fired warning shots into the air to disperse the group but they didn't move, so shots were fired," he said.
The International Committee of the Red Cross and Myanmar Red Cross said in a statement they had transferred three "seriously injured patients" to hospital in the state capital of Sittwe, as well as two other "civilians" to a local hospital.
"The ICRC is concerned about increasing numbers of civilian casualties during the recent weeks, and urge all parties to the conflict to protect the civilian population in line with International Humanitarian Law," said Stephan Sakalian, head of delegation in Myanmar for the ICRC.
Rakhine came to global attention after about 730,000 Rohingya Muslims crossed into Bangladesh fleeing a military crackdown in response to militant attacks in 2017. UN investigators have called for senior military officers to be prosecuted over allegations of mass killings, gang rapes and arson. The military denies widespread wrongdoing.
More recently, civilians have been caught up in clashes between the military and the Arakan Army, an insurgent group that recruits from the mainly Buddhist ethnic Rakhine population and is fighting for greater autonomy for the state.
Since November, the fighting has displaced nearly 33,000 people across a large part of central and northern Rakhine and part of neighbouring Chin state, according to the UN Office for the Coordination of Humanitarian Affairs.
The military has initiated legal action against two news organisations, accusing them of defamation for reports that detailed the alleged shooting of civilians by soldiers in March.
Zaw Min Tun told Reuters military and police searching the Rathedaung area's Kyauk Tan village for suspected Arakan Army members found scores of people who were not registered with authorities as living there, so gathered those people in the school.
According to a preliminary investigation, he said, six people were killed after the alleged altercation at 2:00am on Thursday.
As well as those killed in the shooting, eight people had been brought to the hospital in nearby Zedi Pyin village with gunshots wounds, said Maung Soe Win, chairman of the Mayu Region Development Association, a local community group, who was at the hospital.
The injured people said they had been detained for two days when one villager with a mental health problem "got up, shouted and ran away in the middle of the night", said Maung Soe Win.
"Then (security forces) shot the villagers continuously," he told Reuters by phone.
Another military spokesman, Major General Tun Tun Nyi, said on Thursday afternoon the remaining villagers were still being held at the school and investigated for links to the Arakan Army.