
The Friday attack hit a monastery hall around 9:00 am (0230 GMT) in Myaung township of central Sagaing region, killing 11 men and three women, Nway Oo Myaung, a pro-democracy rebel who helped clear bodies, said on Friday.
"Since Buddhist Lent was being marked... older people had entered the meditation centre for three months," he said.
"Those who were killed, their ages were between 50 and 70," he added. "It wasn't a mistaken target, they intentionally attacked a monastery."
A second local opposition fighter, speaking on condition of anonymity, said on Saturday: "Five dead people were from our village and the other nine were from other villages."
"While we were trying to rescue people, the aircraft came to bomb a second time," he said.
It was not immediately possible to contact the Myanmar military for comment.
Myanmar's military sparked a civil war when it snatched power in a 2021 coup, ousting the elected government of Aung San Suu Kyi and detaining the Nobel Peace Prize laureate, reports BSS.
UN investigators last week published a report accusing the military of "indiscriminate and intentional aerial attacks against civilians".