U.N. human rights experts said Wednesday the violence rained down on Rohingya women and children the past six weeks in Rakhine State, western Myanmar, may constitute "crimes against humanity."

"We are particularly worried about the fate of Rohingya women and children subject to serious violations of their human rights, including killings, rapes and forced displacement," two U.N. committees -- one on the rights of women, the other the rights of children -- said in a joint statement.

It also said "we are deeply concerned at the State's failure to put an end to these shocking human rights violations being committed at the behest of the military and other security forces."

The U.N. high commissioner for human rights, Zeid Ra'ad Al Hussein, last month described the Myanmar military operation in Rakhine against the Rohingya as "a textbook example of ethnic cleansing."

The Rohingya are Bengali-speaking Muslims living in predominantly Buddhist Myanmar, where the government considers many to be illegal migrants from Bangladesh.

The Myanmar government also says it is battling Rohingya "terrorists" who triggered the fighting by attacking more than two dozen police posts and an army camp on Aug. 25.

According to U.N. figures, over half a million Rohingya have fled the violence in Myanmar since last August, adding to more than 300,000 refugees in Bangladesh who escaped previous waves of violence.

The committees urged Myanmar to create "adequate conditions to ensure their prompt and durable return to their places of origin, if they so wish, in safety and dignity."

Bangladesh authorities said earlier this week that Myanmar had proposed to take back hundreds of thousands of Rohingya refugees, and the two countries had agreed to set up a working group to plan the process.