While the world has focused on Bangladesh, where some 290,000 Rohingya have fled an army crackdown on the militants in two weeks, a serious humanitarian crisis is also unfolding on the Myanmar side, aid workers say.

Thousands of displaced people have been stranded or left without food for weeks.

The flight of the Rohingya began on Aug. 25 after Rohingya insurgents attacked police posts and an army base in Rakhine state. That triggered an army counter-offensive in which at least 400 people were killed, thousands of houses were burned, villages razed and vast swathes of land depopulated.

Read: Rohingya Face Aid Crisis after Myanmar Violence

"The U.N. and INGOs have not been very welcome in Rakhine and they are not able to operate and ensure the safety and security of their staff and volunteers," said Joy Singhal of the International Federation of Red Cross and Red Crescent Societies (IFRC).

"In such an environment, the government has invited the Red Cross to assist them," Singhal said.

Aid workers worry many Rohingya had been left without food since mid-July, when the World Food Programme (WFP), which had been providing food and cash assistance, was unable to operate.

The U.N. evacuated "non-critical" staff from the area after the government suggested the WFP and international aid groups supported the insurgents shortly after the attacks.

Joy said the government would have the role of "coordination and facilitation," but the "assessment, aid delivery and implementation" would all be managed by the Red Cross.

Thousands of people are still trying to cross mountains, dense bush and rice fields to reach Bangladesh.

The government said it would establish camps for internally displaced people, but the move could spark opposition from some humanitarian experts.

The U.N. objected to the creation of "camp-like" villages for the Myanmar's Rohingya ethnic in April, citing the risk of stoking tensions. The U.N. stressed the importance of allowing displaced people to return to their place of origin and livelihoods.

REUTERS