U.N. peacekeepers in South Sudan have deliberately failed to fulfill their mission in the town of Abyei, Amnesty International charged Tuesday.

Amnesty said the peacekeepers failed to prevent the occupation of Abyei by rival militias and the north Sudanese army in May. It  also criticized the Sudanese army stating it expelled all inhabitants of Abyei town and burned down their homes to prevent their return.

“Charred homes and the shells of looted buildings testify to the horrors that took place in Abyei, which is now a ghost town,” Amnesty stated.

The Sudanese Armed Forces rejected the accusations. Spokesman Al-Sawarmi Khalid Saad said, The army controlled all areas of the three states of Darfur, especially adjacent to the border with the State of South Sudan and the states of North and South Kordofan under full control.

The Army foiled an infiltration attempt by a group of individuals through pursuits and continued searching to all areas and the closure of all entrances that are likely the remnants of the insurgency cross through it, he added.

Last month U.N. Secretary-General Ban Ki-moon's report to the Security Council mentioned the grave situation. “The situation is untenable and adds to the already considerable tensions between the two countries,” he stated.

There was supposed to be a referendum in Abyei, scheduled for January, to decide on whether to join the south or remain a special administrative region in the north. It was later canceled due to the disagreements over who was eligible to vote.