UN deputy spokesman Farhan Haq said the United Nations was "extremely disturbed over the killing by security forces of a 7-year-old child in her home".
"There must be accountability for all the crimes and human rights violations that continue to be perpetrated in Myanmar," he said.
Haq said the UN noted reports of the release of hundreds of demonstrators and remained concerned about ongoing arrests by the military, including of journalists and civil society leaders.
The UN called "for the release of all those arbitrarily detained, including President U Win Myint and State Counsellor Daw Aung San Suu Kyi".
Haq said UN Secretary-General Antonio Guterres and UN special envoy for Myanmar Christine Schraner Burgener "will continue to mobilise international action for the restoration of democracy and human rights in Myanmar".
-AP