Myanmar border guards shot and injured a Rohingya boy playing in a strip of a no-man's land near the Bangladesh border on Thursday, community leaders said.
Ansar Ullah, 10, was hit near barbed-wire fences erected by Myanmar on its side of the buffer zone also known as the zero line.
More than 700,000 Rohingya Muslims were forced to flee Rakhine state in Myanmar last year after a military crackdown that the United Nations has said amounts to "ethnic cleansing".
Most have settled in vast camps in Bangladesh but around 6,000 have stayed put in the buffer zone between the two country's borders.
"Some children were playing near the fence this afternoon when a round of live ammunition fired from the nearby BGP (Myanmar Border Guard Police) post hit Ansar," community leader Dil Mohammad said.
The boy suffered an injury to his thigh and was rushed to a hospital run by Doctors Without Borders (MSF) inside a Rohingya camp for treatment.
Another community leader, Mohammad Arif, expressed outrage.
"Does a 10-year-old unarmed kid look like a threat to them? Shame on them that they fired upon unarmed civilian children," Arif told AFP.
Lieutenant Colonel Manzurul Hasan Khan, a commander from the Border Guard Bangladesh (BGB), said the shot came from the Myanmar side of no-man's land.
But he could not say whether the bullet was fired from a BGP post. "We will send a protest note (to the BGP)," he said.
An MSF spokesman in Cox's Bazar said he had no knowledge of the incident and could not comment at this time.
In the past Myanmar security forces used loudspeakers to urge the Rohingya refugees to leave the area and cross into Bangladesh or face prosecution.
It also deployed hundreds of troops and heavy weaponry which were later withdrawn although refugees have complained of repeated intimidation.
The refugee crisis has strained ties between Bangladesh and Myanmar.
They agreed in November to begin repatriating Rohingya refugees to Myanmar but the process has stalled, with both sides blaming each other for the delay.
Those living in no-man's land -- and many in the Bangladeshi refugee camps -- refuse to return to Myanmar until their safety and citizenship are assured and compensation granted for past injustices.