As reported by MSF, the death toll from violence in Rakhine contrasts sharply with figures given by Myanmar officials who in early September put the death toll from the violence there in the low hundreds.
The crackdown, which followed raids against Myanmar police and security posts by Arakan Rohingya Salvation Army (ARSA) insurgents on August 25, pushed 655,000 members of the Rohingya Muslim minority to seek shelter in neighboring Bangladesh during the following months, according to the latest estimates published by the United Nations on Thursday.
The Myanmar Press Council says police have arrested two journalists working for an global news organization on suspicion of possessing "secret police documents" related to the ongoing crisis in Rakhine state.
Out of the children below age 5 who were killed, 59 percent were shot, 15 percent were burnt to death in their home, 7 percent were beaten to death and 2 percent died in landmine blasts, according to the survey.
But MSF said the peak in deaths coincided with the launch of "clearance operations" by the army and local militias in late August, and were evidence "that Rohingya have been targeted".
Bangladesh and Myanmar have agreed to cooperate on the repatriation of the displaced Rohingya but rights groups have cautioned against any hasty return before peace and stability is restored.
Reuters global communications chief Abbe Serphos said: "We are urgently seeking more information about the circumstances of their arrest and their current situation".
Though more than 1 million ethnic Rohingya Muslims have lived in the country for generations, they were stripped of their citizenship, denied nearly all rights and labelled stateless.
She said the findings were staggering, in terms of the numbers of people who reported a family member dead as a result of violence and horrific ways in which they said they were killed or injured. About 630,000 Rohingya have fled Myanmar into Bangladesh to escape what the United Nations has called "ethnic cleansing".
"We met and spoke with survivors of violence in Myanmar, who are now sheltering in overcrowded and unsanitary camps in Bangladesh", said the group's medical director Sidney Wong.
The Health Ministry has sent a field hospital to Bangladesh for Rohingya refugees from Myanmar, the General Staff said yesterday.
The group also warned there was still very limited access for aid groups into Rakhine state.
Aerial view of a burned Rohingya village near Maungdaw, northern Rakhine state, Myanmar, Nov 12, 2017.