Police barred foreign aid workers from reaching cyclone survivors in hard-hit areas Tuesday, while emergency food shipments backed up at the main airport for Myanmar’s biggest city.

Relief workers reported some storm survivors were being given spoiled or poor-quality food rather than nutrition-rich biscuits sent by international donors, adding to fears that the ruling military junta in the Southeast Asian country could be misappropriating assistance.

U.N. officials warned that the threat was escalating for the 2 million people facing disease and hunger in low-lying areas battered by the storm unless relief efforts increased dramatically.

Ten days after the tempest, reaching the worst-affected areas was getting more and more difficult.

Checkpoints manned by armed police were set up Tuesday on roads leading to the Irrawaddy River delta and all international aid workers and journalists were turned back by officers who took down their names and passport numbers. Drivers were interrogated.